AP Microeconomics · ⁨AP Ekonomi Mikro⁩

Tips

Mikroekonomi AP mencakup kelangkaan dan biaya peluang, penawaran dan permintaan, elastisitas, produksi dan biaya, empat struktur pasar, pasar faktor, serta kegagalan pasar dengan intervensi pemerintah. Silabusnya kecil namun dipelajari mendalam.

Grafik adalah jawabannya. Sebagian besar nilai soal respons bebas diberikan untuk diagram yang dilabeli dengan benar — sumbu bernama, kurva dilabeli, keseimbangan baru ditandai dan arah pergeseran ditunjukkan. Penjelasan tertulis mengenai pergeseran yang tidak Anda gambar hanya mendapatkan nilai sangat sedikit.

Latihlah menggambar kurva tersebut dengan cepat dan benar secara manual, terutama kurva biaya dan persaingan sempurna versus monopoli, yang muncul secara konstan.

Catatan mencakup keenam unit dengan kurva biaya dan diagram pasar yang digambar alih-alih dijelaskan. FRQs masa lalu beserta pedoman penskoran tersedia di perpustakaan. Nilai Mikro sering kali diberikan untuk menunjukkan pergeseran dan akibatnya, sehingga jawaban yang dikerjakan mempertahankan grafik sebagai pusat perhatian.

Train all vocabulary · ⁨Latih semua kosakata⁩

Past Papers · ⁨Soal-Soil Masa Lalu⁩

Basic Economic Concepts · ⁨Konsep Ekonomi Dasar⁩

Watch lesson · ⁨Tonton pelajaran⁩

Open this topic on its own page · ⁨Buka topik ini di halaman sendiri⁩

1.1

Scarcity

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (MKT-1): Most resources are scarce, and in most cases the use of resources involves constraints and trade-offs.

Learning Objective MKT-1.A: Define resources and the cause(s) of their scarcity.

MKT-1.A.1 Economic trade-offs arise from the lack of sufficient resources (scarcity) to meet society's wants and needs.
MKT-1.A.2 Most factors of production (such as land, labor, and capital) are scarce, but some factors of production (such as established knowledge) may not be scarce due to their non-rival nature.

Bahasa Indonesia

Pemahaman Abadi (MKT-1): Sebagian besar sumber daya terbatas, dan dalam sebagian besar kasus penggunaan sumber daya melibatkan batasan dan trade-off.

Tujuan Pembelajaran MKT-1.A: Definisikan sumber daya dan penyebab keterbatasannya.

MKT-1.A.1 Trade-off ekonomi timbul dari kurangnya sumber daya yang cukup (kelangkaan) untuk memenuhi keinginan dan kebutuhan masyarakat.
MKT-1.A.2 Sebagian besar faktor produksi (seperti tanah, tenaga kerja, dan modal) terbatas, tetapi beberapa faktor produksi (seperti pengetahuan yang mapan) mungkin tidak terbatas karena sifat non-rival mereka.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

An outdoor market: markets allocate scarce resources among competing uses

Economics 经济学 begins with one stubborn fact: people's wants are effectively unlimited, but the resources 资源 to satisfy them are limited. This gap is scarcity 稀缺性, and it is why economics exists – if everything were free and endless, there would be nothing to decide.

The resources (the factors of production 生产要素) are land (natural resources), labor 劳动 (human effort), capital 资本 (tools, machines, buildings), and entrepreneurship 企业家才能 (organizing the other three and taking risks). Because these are scarce, every economy must answer three questions: what to produce, how to produce it, and for whom to produce.

Scarcity forces choice, and every choice has an opportunity cost 机会成本 – the value of the next-best alternative you give up. This single idea runs through the whole course: the true cost of anything is what you sacrifice to get it, not just the money you pay.

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
Economics/ˌiːkəˈnɒmɪks/	Ekonomi
resources/rɪˈzɔːsɪz/	sumber daya
scarcity/ˈskeəsɪti/	kelangkaan
factors of production/ˈfæktəz ɒv prəˈdʌkʃn/	faktor produksi
labor/ˈleɪbə/	Tenaga kerja
capital/ˈkæpɪtl/	modal
entrepreneurship/ˌɒntrɪprəˈnjʊəʃɪp/	kewirausahaan
opportunity cost/ɒpəˈtjuːnɪti kɒst/	biaya peluang

1.2

Resource Allocation and Economic Systems

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (MKT-1): Most resources are scarce, and in most cases the use of resources involves constraints and trade-offs.

Learning Objective MKT-1.B: Define how resource allocation is influenced by the economic system adopted by society.

MKT-1.B.1 Resource allocation involves answering three basic questions: What goods and services to produce? How to produce those goods and services? And who consumes those goods and services?
MKT-1.B.2 Resource allocation is significantly influenced by the economic system adopted by society, such as command economy, market economy, or mixed economy. Each system involves a particular set of institutional arrangements and a coordinating mechanism for allocating scarce resources and distributing output.

Bahasa Indonesia

Pemahaman Abadi (MKT-1): Sebagian besar sumber daya terbatas, dan dalam sebagian besar kasus penggunaan sumber daya melibatkan batasan dan trade-off.

Tujuan Pembelajaran MKT-1.B: Definisikan bagaimana alokasi sumber daya dipengaruhi oleh sistem ekonomi yang diadopsi oleh masyarakat.

MKT-1.B.1 Alokasi sumber daya melibatkan jawaban atas tiga pertanyaan dasar: Barang dan jasa apa yang harus diproduksi? Bagaimana memproduksi barang dan jasa tersebut? Dan siapa yang mengonsumsi barang dan jasa tersebut?
MKT-1.B.2 Alokasi sumber daya sangat dipengaruhi oleh sistem ekonomi yang dianut oleh masyarakat, seperti ekonomi komando, ekonomi pasar, atau ekonomi campuran. Setiap sistem melibatkan serangkaian tata kelola institusional tertentu dan mekanisme koordinasi untuk mengalokasikan sumber daya yang langka serta mendistribusikan output.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

An economic system 经济体制 is a society's way of answering the three questions.

Economic systems form a spectrum from a free market to full government planning

In a market economy 市场经济, private buyers and sellers decide through prices; self-interest and competition coordinate them (the "invisible hand").
In a command economy 计划经济, the government owns resources and plans production.
Real economies are mixed 混合经济 – mostly markets, with government providing some goods and correcting problems.

The key advantage of markets is that prices carry information and incentives 激励 automatically, with no central planner needed.

Explore · ⁨Jelajahi⁩

Explore how prices coordinate a market · ⁨Jelajahi bagaimana harga mengoordinasikan pasar⁩

In a market economy no one is in charge, yet the price finds the level where quantity supplied meets quantity demanded. Drag the demand and supply lines and watch the equilibrium price act as a signal and an incentive. · ⁨Dalam ekonomi pasar tidak ada yang berkuasa, namun harga menemukan titik di mana jumlah yang ditawarkan bertemu dengan jumlah yang diminta. Gerakkan garis permintaan dan penawaran dan perhatikan bagaimana harga keseimbangan bertindak sebagai sinyal dan insentif.⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
economic system/ˌiːkəˈnɒmɪk ˈsɪstəm/	sistem ekonomi
market economy/ˈmɑːkɪt ɪˈkɒnəmi/	ekonomi pasar
command economy/kəˈmænd ɪˈkɒnəmi/	ekonomi komando
mixed/mɪkst/	campuran
incentives/ɪnˈsentɪvz/	insentif

1.3

The Production Possibilities Curve

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (MKT-1): Most resources are scarce, and in most cases the use of resources involves constraints and trade-offs.

Learning Objective MKT-1.C: a. Define (using graphs as appropriate) the production possibilities curve (PPC) and related terms. b. Explain (using graphs as appropriate) how the production possibilities curve (PPC) illustrates opportunity costs, trade-offs, inefficiency, efficiency, and economic growth or contraction under various conditions. c. Calculate (using data from PPCs or tables as appropriate) opportunity cost.

MKT-1.C.1 The PPC is a model used to show the trade-offs associated with allocating resources.
MKT-1.C.2 The PPC can be used to illustrate the concepts of scarcity, opportunity cost, efficiency, underutilized resources, and economic growth or contraction.
MKT-1.C.3 The shape of the PPC depends on whether opportunity costs are constant, increasing, or decreasing.
MKT-1.C.4 The PPC can shift due to changes in factors of production as well as changes in productivity/technology.
MKT-1.C.5 Economic growth results in an outward shift of the PPC.

Bahasa Indonesia

Pemahaman Abadi (MKT-1): Sebagian besar sumber daya terbatas, dan dalam sebagian besar kasus penggunaan sumber daya melibatkan batasan dan trade-off.

Tujuan Pembelajaran MKT-1.C: a. Definisikan (menggunakan grafik sesuai kebutuhan) kurva kemungkinan produksi (PPC) dan istilah-istilah terkait. b. Jelaskan (menggunakan grafik sesuai kebutuhan) bagaimana kurva kemungkinan produksi (PPC) mengilustrasikan biaya peluang, trade-off, inefisiensi, efisiensi, dan pertumbuhan atau kontraksi ekonomi di bawah berbagai kondisi. c. Hitung (menggunakan data dari PPCs atau tabel yang sesuai) biaya peluang.

MKT-1.C.1 PPC adalah model yang digunakan untuk menunjukkan trade-off yang terkait dengan alokasi sumber daya.
MKT-1.C.2 PPC dapat digunakan untuk mengilustrasikan konsep kelangkaan, biaya peluang, efisiensi, sumber daya yang tidak termanfaatkan sepenuhnya, serta pertumbuhan atau kontraksi ekonomi.
MKT-1.C.3 Bentuk PPC bergantung pada apakah biaya peluang bersifat konstan, meningkat, atau menurun.
MKT-1.C.4 PPC dapat bergeser akibat perubahan dalam faktor-faktor produksi serta perubahan dalam produktivitas/teknologi.
MKT-1.C.5 Pertumbuhan ekonomi menyebabkan pergeseran PPC ke arah luar.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

The production possibility frontier

The production possibilities curve (PPC) 生产可能性曲线 shows the maximum combinations of two goods an economy can produce with its resources and technology fully and efficiently used.

Points on, inside, and outside the production possibilities curve

Points on the curve are efficient 有效率; points inside are inefficient (wasted or unemployed resources); points outside are currently unattainable 无法实现.
The PPC's downward slope shows opportunity cost: making more of one good means making less of the other. The slope at a point is the opportunity cost of the good on the horizontal axis.
A bowed-out (concave) PPC shows increasing opportunity cost – resources are not equally suited to both goods, so making more of one costs ever more of the other. A straight-line PPC means constant opportunity cost.
Economic growth 经济增长 (more resources, better technology) shifts the whole curve outward.

Exam skill: be ready to read opportunity cost off a PPC, decide if a point is efficient/inefficient/unattainable, and explain what shifts the curve.

A production possibilities curve: efficient, inefficient, and unattainable points

Explore · ⁨Jelajahi⁩

Explore the production possibilities curve · ⁨Jelajahi kurva kemungkinan produksi⁩

Making more of one good means giving up some of the other — that trade-off is the opportunity cost, and the bowed shape shows the law of increasing opportunity cost. Drag along the curve, then grow the economy to push the whole frontier out. · ⁨Memproduksi lebih banyak satu jenis barang berarti harus mengorbankan sebagian dari barang lainnya — pengorbanan ini adalah biaya peluang, dan bentuk lengkungnya menunjukkan hukum biaya peluang meningkat. Seret sepanjang kurva, lalu kembangkan ekonomi untuk mendorong seluruh batas produksi ke luar.⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
production possibilities curve (PPC)/prəˈdʌkʃn ˌpɒsəˈbɪlɪtiz kɜːv/	Kurva kemungkinan produksi (PPC)
efficient/ɪˈfɪʃənt/	efisien
unattainable/ʌnəˈteɪnəbl/	tidak dapat dicapai
Economic growth/ˌiːkəˈnɒmɪk ɡrəʊθ/	Pertumbuhan ekonomi

1.4

Comparative Advantage and Gains from Trade

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (MKT-2): The consequences of scarcity can be mitigated through specialization in production and by exchange.

Learning Objective MKT-2.A: a. Define absolute advantage and comparative advantage. b. Determine (using data from PPCs or tables as appropriate) absolute and comparative advantage.

MKT-2.A.1 Absolute advantage describes a situation in which an individual, business, or country can produce more of a good or service than any other producer with the same quantity of resources.
MKT-2.A.2 Comparative advantage describes a situation in which an individual, business, or country can produce a good or service at a lower opportunity cost than another producer.

Learning Objective MKT-2.B: a. Explain (using data from PPCs or tables as appropriate) how specialization according to comparative advantage with appropriate terms of trade can lead to gains from trade. b. Calculate (using data from PPCs or tables as appropriate) mutually beneficial terms of trade.

MKT-2.B.1 Production specialization according to comparative advantage, not absolute advantage, results in exchange opportunities that lead to consumption possibilities beyond the PPC.
MKT-2.B.2 Comparative advantage and opportunity costs determine the terms of trade for exchange under which mutually beneficial trade can occur.

Bahasa Indonesia

Pemahaman Abadi (MKT-2): Konsekuensi dari kelangkaan dapat dimitigasi melalui spesialisasi dalam produksi dan melalui pertukaran.

Tujuan Pembelajaran MKT-2.A: a. Definisikan keunggulan mutlak dan keunggulan komparatif. b. Tentukan (menggunakan data dari PPCs atau tabel yang sesuai) keunggulan mutlak dan keunggulan komparatif.

MKT-2.A.1 Keunggulan mutlak menggambarkan situasi di mana seseorang, perusahaan, atau negara dapat menghasilkan lebih banyak barang atau jasa daripada produsen lain dengan jumlah sumber daya yang sama.
MKT-2.A.2 Keunggulan komparatif menggambarkan situasi di mana seseorang, perusahaan, atau negara dapat menghasilkan barang atau jasa dengan biaya peluang yang lebih rendah dibandingkan produsen lain.

Tujuan Pembelajaran MKT-2.B: a. Jelaskan (menggunakan data dari PPCs atau tabel yang sesuai) bagaimana spesialisasi menurut keunggulan komparatif dengan suku perdagangan yang tepat dapat mengarah pada keuntungan dari perdagangan. b. Hitung (menggunakan data dari PPCs atau tabel yang sesuai) suku perdagangan yang saling menguntungkan.

MKT-2.B.1 Spesialisasi produksi berdasarkan keunggulan komparatif, bukan keunggulan mutlak, menghasilkan peluang pertukaran yang mengarah pada kemungkinan konsumsi yang melebihi PPC.
MKT-2.B.2 Keunggulan komparatif dan biaya peluang menentukan syarat perdagangan untuk pertukaran di mana perdagangan yang saling menguntungkan dapat terjadi.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Two producers can both gain from trade by specializing 专业化.

Comparative advantage comes from differently-sloped production possibilities curves

A producer has an absolute advantage 绝对优势 in a good if it can make more of it with the same resources.
A producer has a comparative advantage 比较优势 if it has the lower opportunity cost for that good. Comparative advantage – not absolute – determines who should specialize.
Compute opportunity cost from output data: for each producer, one unit of good X costs (units of Y) $\div$ (units of X). The producer who gives up less Y should make X.
Both sides gain if they trade at a rate between their two opportunity costs – the terms of trade 贸易条件. Specializing by comparative advantage lets total output exceed what either could make alone, so consumption can lie outside each producer's own PPC.

Worked example. Anna can make $20$ shirts or $10$ tables a day; Ben can make $12$ shirts or $12$ tables. For Anna one table costs $\tfrac{20}{10}=2$ shirts; for Ben it costs $\tfrac{12}{12}=1$ shirt. Ben gives up fewer shirts, so Ben specializes in tables and Anna in shirts. Any terms of trade between $1$ and $2$ shirts per table – say $1.5$ – leaves both better off than producing alone.

Exam skill: these calculations appear almost every year – practice finding comparative advantage from both output tables and input tables, and stating a valid terms-of-trade range.

Comparative advantage goes to the producer with the lower opportunity cost

Container shipping: comparative advantage and trade let countries specialise and gain

Explore · ⁨Jelajahi⁩

See why trade lets you consume beyond the frontier · ⁨Lihat mengapa perdagangan memungkinkan Anda mengonsumsi melebihi batas produksi⁩

A producer should specialize where its opportunity cost is lowest, then trade for the rest. Because the terms of trade lie between the two producers' costs, trade lets a country consume outside its own production frontier. · ⁨Seorang produsen harus berspesialisasi pada titik di mana biaya peluang-nya terendah, kemudian berdagang untuk kebutuhan sisanya. Karena rasio perdagangan berada di antara biaya kedua produsen, perdagangan memungkinkan suatu negara mengonsumsi di luar batas produksinya sendiri.⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
specializing/ˈspeʃəlaɪzɪŋ/	Spesialisasi
absolute advantage/ˈæbsəluːt ədˈvæntɪdʒ/	keunggulan absolut
comparative advantage/kəmˈpærətɪv ədˈvæntɪdʒ/	keunggulan komparatif
terms of trade/tɜːmz ɒv treɪd/	syarat pertukaran

1.5

Cost-Benefit Analysis

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (CBA-1): Rational economic decisions require the evaluation of costs and benefits.

Learning Objective CBA-1.A: a. Define opportunity cost. b. Explain the opportunity costs associated with choices. c. Calculate the opportunity costs associated with choices.

CBA-1.A.1 Rational agents consider opportunity costs, whether implicit or explicit, when calculating the total economic costs of any decision.
CBA-1.A.2 Total benefits form the metric "utility" for consumers and total revenue for firms.

Learning Objective CBA-1.B: a. Explain a decision by comparing total benefits and total costs (using a table or a graph when appropriate). b. Calculate total benefits and total costs (using a table or graph where appropriate).

CBA-1.B.1 Total net benefits, the difference between total benefits and total costs, are maximized at the optimal choice.
CBA-1.B.2 Some decisions permit rational agents to look at only marginal benefit and marginal cost. Other decisions cannot be broken down into increments in this way and must be evaluated by looking at total benefits and total costs.

Bahasa Indonesia

Pemahaman Abadi (CBA-1): Keputusan ekonomi yang rasional memerlukan evaluasi terhadap biaya dan manfaat.

Tujuan Pembelajaran CBA-1.A: a. Definisikan biaya peluang. b. Jelaskan biaya peluang yang terkait dengan pilihan-pilihan. c. Hitung biaya peluang yang terkait dengan pilihan-pilihan.

CBA-1.A.1 Agen rasional mempertimbangkan biaya peluang, baik implisit maupun eksplisit, saat menghitung total biaya ekonomi dari setiap keputusan.
CBA-1.A.2 Total manfaat membentuk metrik "utilitas" bagi konsumen dan total pendapatan bagi perusahaan.

Tujuan Pembelajaran CBA-1.B: a. Jelaskan sebuah keputusan dengan membandingkan total manfaat dan total biaya (menggunakan tabel atau grafik sesuai kebutuhan). b. Hitung total manfaat dan total biaya (menggunakan tabel atau grafik sesuai kebutuhan).

CBA-1.B.1 Total manfaat bersih, yaitu selisih antara total manfaat dan total biaya, dimaksimalkan pada pilihan optimal.
CBA-1.B.2 Beberapa keputusan memungkinkan agen rasional untuk hanya melihat manfaat marjinal dan biaya marjinal. Keputusan lainnya tidak dapat dipecah menjadi inkremen dengan cara ini dan harus dievaluasi dengan melihat total manfaat dan total biaya.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Rational decision-makers weigh benefits against costs. An action is worthwhile only when its benefit is at least as large as its cost – including the opportunity cost. Money already spent and unrecoverable is a sunk cost 沉没成本 and should be ignored in decisions: only future costs and benefits matter.

Explore · ⁨Jelajahi⁩

Weigh total benefit against total cost · ⁨Timbang manfaat total terhadap biaya total⁩

A choice is worth it only while the benefit of one more unit beats its cost. Where total revenue meets total cost is the break-even point; past it, extra activity adds more cost than value. · ⁨Suatu pilihan layak dilakukan selama manfaat dari satu unit tambahan melampaui biayanya. Di mana total pendapatan bertemu dengan total biaya adalah titik balik modal; melewatinya, aktivitas tambahan menambah biaya lebih besar daripada nilainya.⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
sunk cost/sʌŋk kɒst/	biaya tenggelam

1.6

Marginal Analysis and Consumer Choice

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (CBA-2): To determine the optimal level at which to pursue an activity whose total benefits exceed total cost, rational economic agents compare marginal benefits and marginal costs.

Learning Objective CBA-2.A: a. Define the key assumptions of consumer choice theory. b. Explain (using a table or graph as appropriate) how a rational consumer's decision making involves the use of marginal benefits and marginal costs. c. Calculate (using a table or a graph when appropriate) how a rational consumer's decision making involves the use of marginal benefits and marginal costs.

CBA-2.A.1 Consumers face constraints and have to make optimal decisions accounting for these constraints.
CBA-2.A.2 In a model of rational consumer choice, consumers are assumed to make choices so as to maximize their total utility.
CBA-2.A.3 Consumers experience diminishing marginal utility in the consumption of goods and services.
CBA-2.A.4 Consumers allocate their limited income to purchase the combination of goods that maximizes their utility by equating/comparing the marginal utility of the last dollar spent on each good.
- Exclusion statement: Indifference curves are beyond the scope of the course and the AP Exam, but equating the ratios of marginal utility to price is within the scope.

Learning Objective CBA-2.B: a. Define marginal analysis and related terms. b. Explain a decision using marginal analysis (using a table or a graph when appropriate).

CBA-2.B.1 Marginal analysis involves comparing the additional benefit of increasing a given activity with the additional cost. Comparing marginal benefit (MB) with marginal cost (MC) helps individuals (firms) decide whether to increase, decrease, or maintain their consumption (production) levels.
CBA-2.B.2 The optimal quantity at any point in time does not depend on fixed costs (sunk costs) or fixed benefits that have already been determined by past choices.
CBA-2.B.3 The optimal quantity is achieved when marginal benefit is equal to marginal cost or where total benefit is maximized.

Bahasa Indonesia

Pemahaman Abadi (CBA-2): Untuk menentukan tingkat optimal di mana aktivitas yang total manfaatnya melebihi total biaya dapat dijalankan, agen ekonomi rasional membandingkan manfaat marjinal dan biaya marjinal.

Tujuan Pembelajaran CBA-2.A: a. Definisikan asumsi-asumsi kunci dari teori pemilihan konsumen. b. Jelaskan (menggunakan tabel atau grafik sesuai kebutuhan) bagaimana pengambilan keputusan konsumen rasional melibatkan penggunaan manfaat marjinal dan biaya marjinal. c. Hitung (menggunakan tabel atau grafik sesuai kebutuhan) bagaimana pengambilan keputusan konsumen rasional melibatkan penggunaan manfaat marjinal dan biaya marjinal.

CBA-2.A.1 Konsumen menghadapi keterbatasan dan harus membuat keputusan optimal dengan memperhitungkan keterbatasan tersebut.
CBA-2.A.2 Dalam model pemilihan konsumen rasional, diasumsikan bahwa konsumen membuat pilihan sedemikian rupa untuk memaksimalkan total utilitas mereka.
CBA-2.A.3 Konsumen mengalami diminishing marginal utility dalam konsumsi barang dan jasa.
CBA-2.A.4 Konsumen mengalokasikan pendapatan terbatas mereka untuk membeli kombinasi barang yang memaksimalkan utilitas mereka dengan menyamakan/membandingkan utilitas marjinal dari dolar terakhir yang dihabiskan untuk setiap barang.
- Pernyataan pengecualian: Kurva induferensi berada di luar cakupan kurikulum dan Ujian AP, namun menyamakan rasio utilitas marjinal terhadap harga berada dalam cakupan.

Tujuan Pembelajaran CBA-2.B: a. Definisikan analisis marjinal dan istilah-istilah terkait. b. Jelaskan sebuah keputusan menggunakan analisis marjinal (menggunakan tabel atau grafik sesuai kebutuhan).

CBA-2.B.1 Analisis marjinal melibatkan perbandingan tambahan manfaat dari peningkatan suatu aktivitas tertentu dengan tambahan biayanya. Membandingkan manfaat marjinal (MB) dengan biaya marjinal (MC) membantu individu (perusahaan) memutuskan untuk meningkatkan, menurunkan, atau mempertahankan tingkat konsumsi (produksi) mereka.
CBA-2.B.2 Kuantitas optimal pada titik waktu tertentu tidak bergantung pada biaya tetap (biaya tenggelam) atau manfaat tetap yang telah ditentukan oleh pilihan masa lalu.
CBA-2.B.3 Kuantitas optimal tercapai ketika manfaat marjinal sama dengan biaya marjinal atau di mana total manfaat dimaksimalkan.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Most real decisions are not "all or nothing" but "a little more or a little less." Marginal analysis 边际分析 compares the marginal benefit 边际收益 (the benefit of one more unit) with the marginal cost 边际成本 (the cost of one more unit).

Each extra unit consumed gives less extra satisfaction (diminishing marginal utility)

Decision rule: keep doing the activity while marginal benefit $>$ marginal cost; stop where MB $=$ MC. That point maximizes net benefit (total benefit minus total cost).
Consumers get utility 效用 (satisfaction) from goods, but each extra unit usually gives less added satisfaction – the law of diminishing marginal utility 边际效用递减法则.
A consumer maximizes total utility by the utility-maximizing rule: spend so that the marginal utility per dollar is equal across all goods, $\dfrac{MU_x}{P_x}=\dfrac{MU_y}{P_y}$, using up the whole budget. If one good gives more utility per dollar, buy more of it until the ratios equalize.

Worked example. A consumer is choosing between good X ($MU_x=20$, $P_x=\$2$) and good Y ($MU_y=15$, $P_y=\$1$). The utility per dollar is $\tfrac{20}{2}=10$ for X but $\tfrac{15}{1}=15$ for Y. Y delivers more satisfaction per dollar, so the consumer should buy more Y and less X; as they do, $MU_y$ falls and $MU_x$ rises until $\tfrac{MU_x}{2}=\tfrac{MU_y}{1}$ and the budget is spent.

Exam skill: the "MB = MC" logic and the "equal MU-per-dollar" rule are tested repeatedly – be able to find the optimal quantity from a table and explain why it is optimal.

Rational choice: keep going while marginal benefit exceeds marginal cost, stopping where they are equal

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
Marginal analysis/ˈmɑːdʒɪnl əˈnæləsɪs/	Analisis marginal
marginal benefit/ˈmɑːdʒɪnl ˈbenɪfɪt/	manfaat marginal
marginal cost/ˈmɑːdʒɪnl kɒst/	biaya marjinal
utility/juːˈtɪlɪti/	utilitas
law of diminishing marginal utility/lɔː ɒv dɪˈmɪnɪʃɪŋ ˈmɑːdʒɪnl juːˈtɪlɪti/	hukum utilitas marginal menurun

1.6

Exam tips

Opportunity cost is the next-best alternative given up; ignore sunk costs in any decision.
Comparative advantage (lower opportunity cost) determines specialisation and the gains from trade.
Apply marginal analysis: keep doing an activity while MB > MC, stopping where MB = MC.
Maximise utility by equalising the marginal utility per dollar across goods.
Read opportunity cost off the PPC slope; a bowed curve shows increasing cost.

Supply and Demand · ⁨Penawaran dan Permintaan⁩

Watch lesson · ⁨Tonton pelajaran⁩

Open this topic on its own page · ⁨Buka topik ini di halaman sendiri⁩

2.1

Demand

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (MKT-3): Individuals and firms respond to incentives and face constraints.

Learning Objective MKT-3.A: a. Define (using graphs as appropriate) key terms and factors related to consumer decision making and the law of demand. b. Explain (using graphs as appropriate) the relationship between price and quantity demanded and how buyers respond to incentives and constraints.

MKT-3.A.1 A well-defined system of property rights is necessary for the market system to function well.
MKT-3.A.2 Economic agents respond to incentives.
MKT-3.A.3 Individuals often respond to incentives, such as those presented by prices, but also face constraints, such as income, time, and legal and regulatory frameworks.
MKT-3.A.4 The law of demand suggests that a change in the own-price causes a change in quantity demanded in the opposite direction and a movement along a demand (marginal benefit) curve.
MKT-3.A.5 The conceptual relationship between price and quantity stated by the law of demand leads to downward-sloping demand curves explained by the income effect and substitution effect and/or by diminishing marginal utility.
MKT-3.A.6 The market demand curve (schedule) is derived from the summation of individual demand curves (schedules).

Learning Objective MKT-3.B: Explain (using graphs as appropriate) buyers' responses to changes in incentives and constraints.

MKT-3.B.1 Changes in the determinants of consumer demand can cause the demand curve to shift.

Bahasa Indonesia

Pemahaman Berkelanjutan (MKT-3): Individu dan perusahaan merespons insentif dan menghadapi keterbatasan.

Tujuan Pembelajaran MKT-3.A: a. Definisikan (menggunakan grafik jika sesuai) istilah kunci dan faktor-faktor yang berkaitan dengan pengambilan keputusan konsumen dan hukum permintaan. b. Jelaskan (menggunakan grafik jika sesuai) hubungan antara harga dan jumlah yang diminta serta bagaimana pembeli merespons insentif dan keterbatasan.

MKT-3.A.1 Sistem hak milik yang terdefinisi dengan jelas diperlukan agar sistem pasar berfungsi dengan baik.
MKT-3.A.2 Agen ekonomi merespons insentif.
MKT-3.A.3 Individu sering kali merespons insentif, seperti yang ditampilkan oleh harga, tetapi juga menghadapi keterbatasan, seperti pendapatan, waktu, dan kerangka kerja hukum serta regulasi.
MKT-3.A.4 Hukum permintaan menunjukkan bahwa perubahan pada harga sendiri menyebabkan perubahan dalam jumlah yang diminta ke arah yang berlawanan dan pergerakan sepanjang kurva permintaan (manfaat marjinal).
MKT-3.A.5 Hubungan konseptual antara harga dan jumlah yang diminta yang dinyatakan oleh hukum permintaan menghasilkan kurva permintaan yang menurun yang dijelaskan oleh efek pendapatan dan efek substitusi dan/atau oleh manfaat marjinal yang semakin berkurang.
MKT-3.A.6 Kurva permintaan pasar (jadwal) diturunkan dari penjumlahan kurva permintaan individu (jadwal).

Tujuan Pembelajaran MKT-3.B: Jelaskan (menggunakan grafik jika sesuai) respons pembeli terhadap perubahan insentif dan keterbatasan.

MKT-3.B.1 Perubahan dalam penentu permintaan konsumen dapat menyebabkan kurva permintaan bergeser.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Shoppers in a market: demand shows how quantity demanded responds to price

Supply & demand: a shift raises P and Q

A market works only where property rights 产权 are well defined – owners can use, exclude others from, and trade their resources; without them, prices cannot coordinate exchange. Within that framework, the two forces are demand and supply.

Demand 需求 is the relationship between the price of a good and the quantity buyers are willing and able to buy. The law of demand 需求定律 says price and quantity demanded move in opposite directions, so the demand curve slopes downward. Two reasons: the substitution effect 替代效应 (when a good gets pricier, buyers switch to alternatives) and the income effect 收入效应 (a higher price shrinks real purchasing power).

The demand curve slopes down; income, tastes, and related prices shift it

Distinguish a change in quantity demanded (a move along the curve, caused only by the good's own price) from a change in demand (a shift of the whole curve). Demand shifts with the determinants 决定因素, remembered as TRIBE:

Tastes/preferences,
Related goods – a rise in the price of a substitute 替代品 raises demand; a rise in the price of a complement 互补品 lowers it,
Income – for a normal good 正常商品 more income raises demand; for an inferior good 低档商品 it lowers it,
Buyers (number of consumers),
Expectations of future price or income.

The market demand curve is the horizontal summation 水平相加 of every individual buyer's demand curve – at each price, add up the quantities all buyers want. That is why more buyers (the B above) shifts the whole market curve to the right.

Explore · ⁨Jelajahi⁩

Shift demand and watch price and quantity · ⁨Geser permintaan dan amati harga serta kuantitas⁩

The demand curve slopes down: lower price, more wanted. A change in income, tastes or related-good prices shifts the whole curve, moving the equilibrium. · ⁨Kurva permintaan menurun: harga lebih rendah, lebih banyak diminati. Perubahan pendapatan, selera, atau harga barang terkait menggeser seluruh kurva, menggerakkan keseimbangan.⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
property rights/ˈprɒpəti raɪts/	hak milik
Demand/dɪˈmænd/	Permintaan
law of demand/lɔː ɒv dɪˈmænd/	hukum permintaan
substitution effect/ˌsʌbstɪˈtjuːʃn ɪˈfekt/	efek substitusi
income effect/ˈɪŋkʌm ɪˈfekt/	efek pendapatan
determinants/dɪˈtɜːmɪnənts/	determinan
substitute/ˈsʌbstɪtjuːt/	substitusi
complement/ˈkɒmplɪmənt/	komplemen
normal good/ˈnɔːml ɡʊd/	barang normal
inferior good/ɪnˈfɪərɪə ɡʊd/	barang inferior
horizontal summation/ˌhɒrɪˈzɒntl sʌˈmeɪʃn/	Penjumlahan horizontal

2.2

Supply

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (MKT-3): Individuals and firms respond to incentives and face constraints.

Learning Objective MKT-3.C: a. Define (using graphs as appropriate) the law of supply. b. Explain (using graphs as appropriate) the relationship between price and quantity supplied.

MKT-3.C.1 A change in own-price causes a change in quantity supplied in the same direction and a movement along a supply curve.
MKT-3.C.2 The market supply curve (schedule) is derived from the summation of individual supply curves (schedules). The market supply curve is upward-sloping.

Learning Objective MKT-3.D: Explain (using graphs as appropriate) producers' (sellers') responses to changes in incentives and technology.

MKT-3.D.1 Changes in the determinants of supply can cause the supply curve to shift.

Bahasa Indonesia

Pemahaman Berkelanjutan (MKT-3): Individu dan perusahaan merespons insentif dan menghadapi keterbatasan.

Tujuan Pembelajaran MKT-3.C: a. Definisikan (menggunakan grafik yang sesuai) hukum penawaran. b. Jelaskan (menggunakan grafik jika sesuai) hubungan antara harga dan jumlah yang ditawarkan.

MKT-3.C.1 Perubahan pada harga sendiri menyebabkan perubahan dalam jumlah yang ditawarkan ke arah yang sama dan pergerakan sepanjang kurva penawaran.
MKT-3.C.2 Kurva penawaran pasar (jadwal) diturunkan dari penjumlahan kurva penawaran individu (jadwal). Kurva penawaran pasar memiliki kemiringan positif.

Tujuan Pembelajaran MKT-3.D: Jelaskan (menggunakan grafik jika sesuai) respons produsen (penjual) terhadap perubahan insentif dan teknologi.

MKT-3.D.1 Perubahan dalam pen penawar dapat menyebabkan kurva penawaran bergeser.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

A shift in supply

Supply 供给 is the relationship between price and the quantity sellers will offer. The law of supply 供给定律: price and quantity supplied move in the same direction, so the supply curve slopes upward (higher prices cover higher marginal costs and reward more output).

The supply curve slopes up; costs, technology, tax, and subsidy shift it

Again separate a change in quantity supplied (movement along the curve, from the good's own price) from a change in supply (a shift). Supply shifts with input prices, technology, taxes and subsidies 补贴, prices of other goods a firm could make, number of sellers, and expectations. Just like demand, the market supply curve is the horizontal sum of individual firms' supply curves – add the quantities all firms offer at each price – so more sellers shifts market supply to the right.

Exam skill: on the free-response section you must draw correctly labeled supply-and-demand graphs and shift the right curve in the right direction – decide first whether the event changes an "own price" (move along) or a determinant (shift).

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
Supply/səˈplaɪ/	Penawaran
law of supply/lɔː ɒv səˈplaɪ/	hukum penawaran
subsidies/ˈsʌbsɪdiz/	subsidi

2.3

Price Elasticity of Demand

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (MKT-3): Individuals and firms respond to incentives and face constraints.

Learning Objective MKT-3.E: a. Define measures of elasticity. b. Explain (using graphs where appropriate) measures of elasticity and the impact of a given price change on total revenue or total expenditure. c. Calculate (using data from a graph or a table as appropriate) measures of elasticity.

MKT-3.E.1 Economists use the concept of elasticity to measure the magnitude of percentage changes in quantity owing to any given changes in the own-price, income, and prices of related goods.
MKT-3.E.2 Price elasticity of demand is measured by the percentage change in quantity demanded divided by the percentage change in price or the responsiveness of the quantity demanded to changes in price. Elasticity varies along a linear demand curve, meaning slope is not elasticity.
MKT-3.E.3 Ranges of values of elasticity of demand are described as elastic or inelastic with the separating benchmark being a magnitude of 1, where the change in the price and the change in the quantity demanded are proportional.
- a. When the magnitude of the value of elasticity is greater than 1, the demand is described as being elastic with respect to that price in the range of the given change.
- b. When the magnitude of the value of elasticity is less than 1, the demand is described as being inelastic with respect to that price in the range of the given change.
- c. When the magnitude of the value of elasticity is equal to 1, the demand is described as being unit elastic with respect to that price in the range of the given change.
MKT-3.E.4 The price elasticity of demand depends on certain factors such as the availability of substitutes.
MKT-3.E.5 The impact of a given price change on total revenue or total expenditure will depend on whether demand is elastic, inelastic, or unit elastic.

Bahasa Indonesia

Pemahaman Berkelanjutan (MKT-3): Individu dan perusahaan merespons insentif dan menghadapi keterbatasan.

Tujuan Pembelajaran MKT-3.E: a. Definisikan ukuran keluwesan. b. Jelaskan (menggunakan grafik jika sesuai) ukuran keluwesan dan dampak perubahan harga tertentu terhadap total pendapatan atau total pengeluaran. c. Hitung (menggunakan data dari grafik atau tabel jika sesuai) ukuran keluwesan.

MKT-3.E.1 Ekonom menggunakan konsep keluwesan untuk mengukur besaran perubahan persentase dalam jumlah karena perubahan tertentu pada harga sendiri, pendapatan, dan harga barang terkait.
MKT-3.E.2 Keluwesan harga permintaan diukur oleh perubahan persentase dalam jumlah yang diminta dibagi dengan perubahan persentase dalam harga atau responsivitas jumlah yang diminta terhadap perubahan harga. Keluwesan bervariasi sepanjang kurva permintaan linear, yang berarti kemiringan bukanlah keluwesan.
MKT-3.E.3 Rentang nilai keluwesan permintaan digambarkan sebagai elastis atau inelastis dengan tolak ukur pemisah berupa besaran 1, di mana perubahan harga dan perubahan jumlah yang diminta adalah proporsional.
- a. Ketika besaran nilai keluwesan lebih besar dari 1, permintaan digambarkan sebagai elastis terhadap harga tersebut dalam rentang perubahan yang diberikan.
- b. Ketika besaran nilai keluwesan kurang dari 1, permintaan digambarkan sebagai inelastis terhadap harga tersebut dalam rentang perubahan yang diberikan.
- c. Ketika besaran nilai keluwesan sama dengan 1, permintaan digambarkan sebagai unit elastis terhadap harga tersebut dalam rentang perubahan yang diberikan.
MKT-3.E.4 Keluwesan harga permintaan bergantung pada beberapa faktor seperti ketersediaan barang pengganti.
MKT-3.E.5 Dampak perubahan harga tertentu terhadap total pendapatan atau total pengeluaran akan bergantung pada apakah permintaan bersifat elastis, inelastis, atau unit elastis.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Price elasticity of demand

Price elasticity of demand 需求价格弹性 measures how responsive quantity demanded is to a price change:

$$E_d=\left|\frac{\%\ \Delta\ \text{quantity demanded}}{\%\ \Delta\ \text{price}}\right|.$$

Inelastic versus elastic demand: a small versus large response to a price change

$E_d>1$: elastic 富有弹性 (quantity responds strongly);
$E_d<1$: inelastic 缺乏弹性 (quantity barely responds);
$E_d=1$: unit elastic.

Demand is more elastic when there are more substitutes, the good is a luxury, it takes a large share of income, or buyers have more time to adjust. Elasticity links to total revenue 总收入 ($P\times Q$): if demand is elastic, a price cut raises revenue; if inelastic, a price cut lowers it. Along a straight-line demand curve, elasticity falls as you move down (elastic on top, inelastic at the bottom).

Worked example. A price rise from $\$10$ to $\$12$ (a $+20\%$ change) cuts quantity demanded from $100$ to $85$ (a $-15\%$ change). Then $E_d=\left|\dfrac{-15\%}{20\%}\right|=0.75<1$, so demand is inelastic. Because it is inelastic, the price rise raises total revenue: from $\$10\times100=\$1000$ to $\$12\times85=\$1020$.

Explore · ⁨Jelajahi⁩

Stretch price and measure elasticity · ⁨Tarik harga dan ukur elastisitas⁩

Price elasticity of demand is how strongly quantity responds to price. A steep curve is inelastic (small response); a shallow one is elastic (large response). · ⁨Elastisitas harga terhadap permintaan mengukur seberapa kuat respons kuantitas terhadap perubahan harga. Kurva yang curam bersifat inelastis (respons kecil); kurva yang landai bersifat elastis (respons besar).⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
Price elasticity of demand/praɪs ɪlæˈstɪsɪti ɒv dɪˈmænd/	Elastisitas harga permintaan
elastic/ɪˈlæstɪk/	anjal
inelastic/ɪnɪˈlæstɪk/	tidak elastis
total revenue/ˈtəʊtl ˈrevənjuː/	pendapatan total

2.4

Price Elasticity of Supply

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (MKT-3): Individuals and firms respond to incentives and face constraints.

MKT-3.E.6 Price elasticity of supply is measured by the percentage change in quantity supplied divided by the percentage change in price, or the responsiveness of the quantity supplied to changes in price.
MKT-3.E.7 Ranges of values of elasticity of supply are described as elastic or inelastic with the separating benchmark being a magnitude of 1, where the change in the price and the change in the quantity supplied are proportional.
- a. When the magnitude of the value of elasticity is greater than 1, the supply is described as being elastic with respect to that price in the range of the given change.
- b. When the magnitude of the value of elasticity is less than 1, the supply is described as being inelastic with respect to that price in the range of the given change.
- c. When the magnitude of the value of elasticity is equal to 1, the supply is described as being unit elastic with respect to that price in the range of the given change.
MKT-3.E.8 The price elasticity of supply depends on certain factors such as the price of alternative inputs.

Bahasa Indonesia

Pemahaman Berkelanjutan (MKT-3): Individu dan perusahaan merespons insentif dan menghadapi keterbatasan.

MKT-3.E.6 Keluwesan harga penawaran diukur oleh perubahan persentase dalam jumlah yang ditawarkan dibagi dengan perubahan persentase dalam harga, atau responsivitas jumlah yang ditawarkan terhadap perubahan harga.
MKT-3.E.7 Rentang nilai keluwesan penawaran digambarkan sebagai elastis atau inelastis dengan tolak ukur pemisah berupa besaran 1, di mana perubahan harga dan perubahan jumlah yang ditawarkan adalah proporsional.
- a. Ketika besaran nilai keluwesan lebih besar dari 1, penawaran digambarkan sebagai elastis terhadap harga tersebut dalam rentang perubahan yang diberikan.
- b. Ketika besaran nilai keluwesan kurang dari 1, penawaran digambarkan sebagai inelastis terhadap harga tersebut dalam rentang perubahan yang diberikan.
- c. Ketika besaran nilai keluwesan sama dengan 1, penawaran digambarkan sebagai unit elastis terhadap harga tersebut dalam rentang perubahan yang diberikan.
MKT-3.E.8 Keluwesan harga penawaran bergantung pada beberapa faktor seperti harga input alternatif.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Price elasticity of supply 供给价格弹性, $E_s=\dfrac{\%\ \Delta\ Q_s}{\%\ \Delta\ P}$, measures how responsive sellers are. Supply is more elastic when firms can adjust output easily – spare capacity, storable goods, and above all more time (supply is more elastic in the long run than the short run).

The same price rise gives a small supply response when PES is below 1, a large one above 1

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
Price elasticity of supply/praɪs ɪlæˈstɪsɪti ɒv səˈplaɪ/	Elastisitas harga penawaran

2.5

Other Elasticities

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (MKT-3): Individuals and firms respond to incentives and face constraints.

MKT-3.E.9 Elasticity can be measured for any determinant of demand or supply, not just the price.
MKT-3.E.10 Income elasticity of demand is measured by the percentage change in the quantity demanded divided by the percentage change in consumers' income. Economists use the income elasticity of demand to determine whether a good is normal or inferior.
MKT-3.E.11 Cross-price elasticity of demand is measured by the percentage change in the quantity demanded of one good divided by the percentage change in the price of another good. Economists use the cross-price elasticity of demand to determine whether goods are substitutes, complements, or not related.

Bahasa Indonesia

Pemahaman Berkelanjutan (MKT-3): Individu dan perusahaan merespons insentif dan menghadapi keterbatasan.

MKT-3.E.9 Keluwesan dapat diukur untuk setiap penentu permintaan atau penawaran, bukan hanya harga.
MKT-3.E.10 Keluwesan pendapatan permintaan diukur oleh perubahan persentase dalam jumlah yang diminta dibagi dengan perubahan persentase dalam pendapatan konsumen. Ekonom menggunakan keluwesan pendapatan permintaan untuk menentukan apakah suatu barang merupakan barang normal atau inferior.
MKT-3.E.11 Elastisitas silang permintaan diukur oleh persentase perubahan jumlah permintaan suatu barang dibagi dengan persentase perubahan harga barang lain. Ekonom menggunakan elastisitas silang permintaan untuk menentukan apakah barang-barang tersebut merupakan pengganti, pelengkap, atau tidak saling terkait.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Cross-price elasticity 交叉价格弹性 $=\dfrac{\%\ \Delta\ Q_x}{\%\ \Delta\ P_y}$: positive for substitutes, negative for complements – the sign tells you the relationship.
Income elasticity 收入弹性 $=\dfrac{\%\ \Delta\ Q}{\%\ \Delta\ \text{income}}$: positive for normal goods (and $>1$ for luxuries), negative for inferior goods.

Worked example. When the price of coffee rises $10\%$, the quantity of tea demanded rises $6\%$: cross-price elasticity $=\dfrac{+6\%}{+10\%}=+0.6$. The positive sign confirms coffee and tea are substitutes. If instead a $5\%$ rise in incomes raised restaurant-meal demand $10\%$, income elasticity $=\dfrac{10\%}{5\%}=+2$ – a normal good, and a luxury since it exceeds $1$.

Cross elasticity: positive for substitutes, negative for complements

Exam skill: you are expected to compute an elasticity, classify it, and read a sign as evidence of substitute/complement or normal/inferior.

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
Cross-price elasticity/krɒs praɪs ɪlæˈstɪsɪti/	Elastisitas silang
Income elasticity/ˈɪŋkʌm ɪlæˈstɪsɪti/	Elastisitas pendapatan

2.6

Market Equilibrium, Consumer Surplus, and Producer Surplus

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (MKT-4): Although equilibria are stable, an economy can move from one equilibrium to another if market conditions change.

Learning Objective MKT-4.A: a. Define (using graphs as appropriate) market equilibrium, consumer surplus, and producer surplus. b. Explain (using graphs as appropriate) how equilibrium price, quantity, consumer surplus, and producer surplus for a good or service are determined. c. Calculate (using data from a graph or table as appropriate) areas of consumer surplus and producer surplus at equilibrium.

MKT-4.A.1 The supply-demand model is a tool for understanding what factors influence prices and quantities and why prices and quantities might differ across markets or change over time.
MKT-4.A.2 In a perfectly competitive market, equilibrium is achieved (and markets clear with no shortages or surpluses) when the price of a good or service brings the quantity supplied and quantity demanded into balance, in the sense that buyers wish to purchase the same quantity that sellers wish to provide.
MKT-4.A.3 Equilibrium price provides information to economic decision-makers to guide resource allocation.
MKT-4.A.4 Economists use consumer surplus and producer surplus to measure the benefits markets create to buyers and sellers and understand market efficiency.
MKT-4.A.5 Market equilibrium maximizes total economic surplus in the absence of market failures, meaning that perfectly competitive markets are efficient.

Bahasa Indonesia

Pemahaman Berkelanjutan (MKT-4): Meskipun keseimbangan bersifat stabil, perekonomian dapat berpindah dari satu keseimbangan ke keseimbangan lain jika kondisi pasar berubah.

Tujuan Pembelajaran MKT-4.A: a. Definisikan (menggunakan grafik secukupnya) keseimbangan pasar, surplus konsumen, dan surplus produsen. b. Jelaskan (menggunakan grafik secukupnya) bagaimana harga keseimbangan, jumlah keseimbangan, surplus konsumen, dan surplus produsen untuk suatu barang atau jasa ditentukan. c. Hitung (menggunakan data dari grafik atau tabel secukupnya) luas surplus konsumen dan surplus produsen pada saat keseimbangan.

MKT-4.A.1 Model permintaan-penyediaan adalah alat untuk memahami faktor-faktor apa yang memengaruhi harga dan jumlah, serta mengapa harga dan jumlah mungkin berbeda antar pasar atau berubah seiring waktu.
MKT-4.A.2 Dalam pasar persaingan sempurna, keseimbangan tercapai (dan pasar bersih tanpa kekurangan atau kelebihan) ketika harga barang atau jasa menyelaraskan jumlah yang ditawarkan dengan jumlah yang diminta, dalam arti bahwa pembeli ingin membeli jumlah yang sama dengan yang ingin ditawarkan penjual.
MKT-4.A.3 Harga keseimbangan memberikan informasi kepada pembuat keputusan ekonomi untuk memandu alokasi sumber daya.
MKT-4.A.4 Ekonom menggunakan surplus konsumen dan surplus produsen untuk mengukur manfaat yang diciptakan pasar bagi pembeli dan penjual serta memahami efisiensi pasar.
MKT-4.A.5 Keseimbangan pasar memaksimalkan total surplus ekonomi dalam ketiadaan kegagalan pasar, yang berarti pasar persaingan sempurna bersifat efisien.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Consumer & producer surplus

Equilibrium 均衡 is where supply meets demand: the equilibrium price clears the market, so quantity demanded equals quantity supplied and there is no shortage or surplus.

Consumer surplus and producer surplus at the market equilibrium

Consumer surplus 消费者剩余 is the area below the demand curve and above the price – the gap between what buyers would pay and what they do pay.
Producer surplus 生产者剩余 is the area above the supply curve and below the price – the gap between the price and sellers' minimum acceptable price.
Their sum is total surplus 总剩余, and the competitive equilibrium maximizes it – this is why free markets are called allocatively efficient 配置有效率.

A market stall selling fruit and vegetables — A real market: many buyers and sellers meet, and price settles where the quantity wanted equals the quantity offered

Explore · ⁨Jelajahi⁩

See consumer and producer surplus · ⁨Lihat surplus konsumen dan produsen⁩

At equilibrium the market clears. The gap between what buyers would pay and the price is consumer surplus; the gap above sellers' costs is producer surplus. · ⁨Pada keseimbangan, pasar seimbang. Selisih antara apa yang pembeli bersedia bayar dengan harga adalah surplus konsumen; selisih di atas biaya penjual adalah surplus produsen.⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
Equilibrium/ˌiːkwɪˈlɪbrɪəm/	Kesetimbangan
Consumer surplus/kənˈsuːmə ˈsɜːpləs/	Surplus konsumen
Producer surplus/prəˈdjuːsə ˈsɜːpləs/	Surplus produsen
total surplus/ˈtəʊtl ˈsɜːpləs/	surplus total
allocatively efficient/ˈæləkətɪvli ɪˈfɪʃənt/	efisien alokatif

2.7

Market Disequilibrium and Changes in Equilibrium

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (MKT-4): Although equilibria are stable, an economy can move from one equilibrium to another if market conditions change.

Learning Objective MKT-4.B: a. Define a surplus and shortage. b. Explain (using graphs where appropriate) how changes in underlying conditions and shocks to a competitive market can alter price, quantity, consumer surplus, and producer surplus. c. Calculate (using data from a graph or table as appropriate) changes in price, quantity, consumer surplus, and producer surplus in response to changes in market conditions or market disequilibrium.

MKT-4.B.1 Whenever markets experience imbalances—creating disequilibrium prices and quantities, surpluses, and shortages—market forces drive price and quantity toward equilibrium.
MKT-4.B.2 Factors that shift the market demand and market supply curves cause price, quantity, consumer surplus, producer surplus, and total economic surplus (within that market) to change. The impact of the change depends on the price elasticities of demand and supply.

Bahasa Indonesia

Pemahaman Berkelanjutan (MKT-4): Meskipun keseimbangan bersifat stabil, perekonomian dapat berpindah dari satu keseimbangan ke keseimbangan lain jika kondisi pasar berubah.

Tujuan Pembelajaran MKT-4.B: a. Definisikan surplus dan kekurangan. b. Jelaskan (menggunakan grafik di mana sesuai) bagaimana perubahan kondisi mendasar dan guncangan pada pasar kompetitif dapat mengubah harga, jumlah, surplus konsumen, dan surplus produsen. c. Hitung (menggunakan data dari grafik atau tabel secukupnya) perubahan harga, jumlah, surplus konsumen, dan surplus produsen sebagai respons terhadap perubahan kondisi pasar atau ketidakseimbangan pasar.

MKT-4.B.1 Setiap kali pasar mengalami ketidakseimbangan—menciptakan harga dan jumlah yang tidak seimbang, kelebihan, dan kekurangan—mekanisme pasar mendorong harga dan jumlah menuju keseimbangan.
MKT-4.B.2 Faktor-faktor yang menggeser kurva permintaan pasar dan kurva penawaran pasar menyebabkan harga, jumlah, surplus konsumen, surplus produsen, dan total surplus ekonomi (dalam pasar tersebut) berubah. Dampak perubahan ini bergantung pada elastisitas permintaan dan penawaran.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Away from equilibrium the market self-corrects: above the equilibrium price there is a surplus 过剩 (excess supply) that pushes price down; below it a shortage 短缺 (excess demand) that pushes price up.

Above equilibrium there is excess supply; below it, excess demand

When a determinant shifts a curve, the equilibrium moves predictably. A single shift gives a definite result for both price and quantity. When both curves shift, one of price or quantity is indeterminate (depends on the relative sizes of the shifts) – a favorite exam trap. Work these out by drawing the shifts.

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
surplus/ˈsɜːpləs/	surplus
shortage/ˈʃɔːtɪdʒ/	kelangkaan

2.8

The Effects of Government Intervention in Markets

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (POL-1): Government policies influence consumer and producer behavior and therefore affect market outcomes.

Learning Objective POL-1.A: a. Define forms of government price and quantity intervention. b. Explain (using graphs where appropriate) how government policies alter consumer and producer behaviors that influence incentives and therefore affect outcomes. c. Calculate (using data from a graph or table where appropriate) changes in market outcomes resulting from government policies.

POL-1.A.1 Some government policies, such as price floors, price ceilings, and other forms of price and quantity regulation, affect incentives and outcomes in all market structures.
POL-1.A.2 Governments use taxes and subsidies to change incentives in ways that influence consumer and producer behavior, shifting the supply and demand curves accordingly.
POL-1.A.3 Taxes and subsidies affect government revenues or costs.
POL-1.A.4 Government intervention in a market producing the efficient quantity through taxes, subsidies, price controls, or quantity controls can only decrease allocative efficiency.
POL-1.A.5 Deadweight loss represents the losses to buyers and sellers as a result of government intervention in an efficient market.
POL-1.A.6 The incidence of taxes and subsidies imposed on goods traded in perfectly competitive markets depends on the elasticity of supply and demand.

Bahasa Indonesia

Pemahaman Berkelanjutan (POL-1): Kebijakan pemerintah memengaruhi perilaku konsumen dan produsen, sehingga berdampak pada hasil pasar.

Tujuan Pembelajaran POL-1.A: a. Definisikan bentuk-bentuk intervensi pemerintah terhadap harga dan jumlah. b. Jelaskan (menggunakan grafik di mana sesuai) bagaimana kebijakan pemerintah mengubah perilaku konsumen dan produsen yang memengaruhi insentif, sehingga berdampak pada hasil. c. Hitung (menggunakan data dari grafik atau tabel di mana sesuai) perubahan hasil pasar yang dihasilkan dari kebijakan pemerintah.

POL-1.A.1 Beberapa kebijakan pemerintah, seperti lantai harga, plafon harga, dan bentuk regulasi harga dan jumlah lainnya, memengaruhi insentif dan hasil di semua struktur pasar.
POL-1.A.2 Pemerintah menggunakan pajak dan subsidi untuk mengubah insentif dengan cara yang memengaruhi perilaku konsumen dan produsen, menggeser kurva penawaran dan permintaan sesuai hal tersebut.
POL-1.A.3 Pajak dan subsidi memengaruhi pendapatan atau biaya pemerintah.
POL-1.A.4 Intervensi pemerintah dalam pasar yang menghasilkan jumlah efisien melalui pajak, subsidi, pengendalian harga, atau pengendalian jumlah hanya dapat menurunkan efisiensi alokatif.
POL-1.A.5 Hilangnya beban mati (deadweight loss) mewakili kerugian bagi pembeli dan penjual akibat intervensi pemerintah di pasar yang efisien.
POL-1.A.6 Beban pajak dan subsidi yang dikenakan pada barang yang diperdagangkan di pasar persaingan sempurna bergantung pada elastisitas penawaran dan permintaan.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

A price ceiling causes a shortage

A tax and the deadweight loss

Governments intervene, usually reducing total surplus:

A price ceiling causes a shortage; a price floor causes a surplus

A price ceiling 价格上限 (a legal maximum, like rent control) below equilibrium causes a persistent shortage.
A price floor 价格下限 (a legal minimum, like a minimum wage) above equilibrium causes a persistent surplus.
An excise tax 消费税 shifts supply up by the tax; the burden (tax incidence 税收归宿) falls more heavily on whichever side is more inelastic.
A subsidy shifts supply down, raising quantity.

Each of these creates deadweight loss 无谓损失 – mutually beneficial trades that no longer happen, shown as a triangle between the curves at the new quantity.

Exam skill: on a graph, be able to shade consumer surplus, producer surplus, government revenue from a tax, and deadweight loss, and say who bears the tax and why.

Explore · ⁨Jelajahi⁩

Add a tax or price control · ⁨Tambahkan pajak atau kontrol harga⁩

A price ceiling below equilibrium causes shortages; a tax drives a wedge between what buyers pay and sellers get, shrinking the quantity traded. · ⁨Batas harga maksimal di bawah keseimbangan menyebabkan kelangkaan; pajak menciptakan kesenjangan antara apa yang dibayar pembeli dan diterima penjual, mengurangi jumlah transaksi.⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
price ceiling/praɪs ˈsiːlɪŋ/	plafon harga
price floor/praɪs flɔː/	lantai harga
excise tax/ekˈsaɪz tæks/	Pajak excise
tax incidence/tæks ˈɪnsɪdəns/	beban pajak
deadweight loss/ˈdedweɪt lɒs/	kerugian berat mati

2.9

International Trade and Public Policy

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (POL-1): Government policies influence consumer and producer behavior and therefore affect market outcomes.

Learning Objective POL-1.B: a. Define tariffs and quotas. b. Explain (using graphs where appropriate) how markets are affected by public policy related to international trade. c. Calculate (using data from a graph or table as appropriate) changes in market outcomes resulting from public policy related to international trade.

POL-1.B.1 Equilibria in competitive markets may be altered by the decision to open an economy to trade with other countries; equilibrium price can be higher or lower than under autarky, and the gap between domestic supply and demand is filled by trade. Opening an economy to trade with other countries affects consumer surplus, producer surplus, and total economic surplus.
POL-1.B.2 Tariffs, which governments sometimes use to influence international trade, affect domestic price, quantity, government revenue, and consumer surplus and total economic surplus.
POL-1.B.3 Quotas can be used to alter quantities produced and therefore affect price, consumer surplus, and total economic surplus.
- Exclusion statement: The graphing of quotas is beyond the scope of the course and the AP Exam, but understanding how quotas affect quantities produced is within the scope.

Bahasa Indonesia

Pemahaman Berkelanjutan (POL-1): Kebijakan pemerintah memengaruhi perilaku konsumen dan produsen, sehingga berdampak pada hasil pasar.

Tujuan Pembelajaran POL-1.B: a. Definisikan tarif dan kuota. b. Jelaskan (menggunakan grafik di mana sesuai) bagaimana pasar dipengaruhi oleh kebijakan publik terkait perdagangan internasional. c. Hitung (menggunakan data dari grafik atau tabel secukupnya) perubahan hasil pasar yang dihasilkan dari kebijakan publik terkait perdagangan internasional.

POL-1.B.1 Keseimbangan di pasar kompetitif dapat diubah oleh keputusan membuka perekonomian untuk berdagang dengan negara lain; harga keseimbangan bisa lebih tinggi atau lebih rendah daripada di bawah autarki, dan kesenjangan antara penawaran domestik dan permintaan domestik dipenuhi oleh perdagangan. Membuka perekonomian untuk berdagang dengan negara lain memengaruhi surplus konsumen, surplus produsen, dan total surplus ekonomi.
POL-1.B.2 Tarif, yang terkadang digunakan pemerintah untuk memengaruhi perdagangan internasional, memengaruhi harga domestik, jumlah, pendapatan pemerintah, surplus konsumen, dan total surplus ekonomi.
POL-1.B.3 Kuota dapat digunakan untuk mengubah jumlah yang diproduksi, sehingga memengaruhi harga, surplus konsumen, dan total surplus ekonomi.
- Pengecualian: Menggambar grafik kuota berada di luar ruang lingkup mata pelajaran dan Ujian AP, namun pemahaman tentang bagaimana kuota memengaruhi jumlah yang diproduksi masuk dalam ruang lingkup.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

When a country opens to trade at a world price 世界价格:

A tariff raises domestic supply, cuts demand, and shrinks imports

If the world price is below the domestic price, the country imports 进口 – consumers gain more than producers lose, so total surplus rises.
If the world price is above the domestic price, the country exports 出口 – producers gain more than consumers lose.

A tariff 关税 (a tax on imports) or a quota 配额 (a limit on imports) raises the domestic price, helps domestic producers, hurts consumers more, and creates deadweight loss. Free trade maximizes total surplus, which is the core efficiency argument for it.

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
world price/wɜːld praɪs/	harga dunia
imports/ɪmˈpɔːts/	impor
exports/ˈekspɔːts/	ekspor
tariff/ˈtærɪf/	tarif
quota/ˈkwəʊtə/	kuota

2.9

Exam tips

Separate a movement along a curve (own price) from a shift (a determinant); a single shift gives a definite result, a double shift leaves one variable indeterminate.
Compute elasticity $E_d=|\%\Delta Q \div \%\Delta P|$; elastic ($>1$) means a price cut raises total revenue, inelastic ($<1$) lowers it.
Read the sign of cross-price elasticity (substitutes $+$, complements $-$) and income elasticity (normal $+$, inferior $-$).
Shade consumer/producer surplus and the deadweight loss from a tax or price control; incidence falls on the more inelastic side.
A price ceiling below equilibrium causes a shortage; a price floor above causes a surplus.

Production, Cost, and the Perfect Competition Model · ⁨Produksi, Biaya, dan Model Persaingan Sempurna⁩

Watch lesson · ⁨Tonton pelajaran⁩

Open this topic on its own page · ⁨Buka topik ini di halaman sendiri⁩

3.1

The Production Function

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-1): Firms' production and cost constraints over different input and output levels shape optimal decisions in the short run and long run.

Learning Objective PRD-1.A: a. Define (using graphs where appropriate) key terms and concepts relating to production and cost. b. Explain (using graphs where appropriate) how production and cost are related in the short run and long run. c. Calculate (using data from a graph or table as appropriate) the various measures of productivity and short-run and long-run costs.

PRD-1.A.1 The production function explains the relationship between inputs and outputs both in the short run and the long run.
PRD-1.A.2 Marginal product and average product change as input usage changes, and hence, total product changes.
PRD-1.A.3 Diminishing marginal returns occur as the firm employs more of one input, holding other inputs constant, to produce a product (output) in the short run.

Bahasa Indonesia

Pemahaman Abadi (PRD-1): Kendala produksi dan biaya perusahaan pada berbagai tingkat input dan output membentuk keputusan optimal dalam jangka pendek dan jangka panjang.

Tujuan Pembelajaran PRD-1.A: a. Definisikan (menggunakan grafik jika sesuai) istilah dan konsep kunci yang berkaitan dengan produksi dan biaya. b. Jelaskan (menggunakan grafik jika sesuai) bagaimana produksi dan biaya saling berkaitan dalam jangka pendek dan jangka panjang. c. Hitung (menggunakan data dari grafik atau tabel jika sesuai) berbagai ukuran produktivitas serta biaya jangka pendek dan jangka panjang.

PRD-1.A.1 Fungsi produksi menjelaskan hubungan antara input dan output baik dalam jangka pendek maupun jangka panjang.
PRD-1.A.2 Produk marjinal dan produk rata-rata berubah seiring perubahan penggunaan input, sehingga total produk juga berubah.
PRD-1.A.3 Hukum hasil marjinal yang semakin menurun terjadi ketika perusahaan menggunakan lebih banyak satu jenis input, sementara input lainnya tetap konstan, untuk memproduksi suatu barang (output) dalam jangka pendek.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

A steel plant: production functions and costs shape how firms supply goods

The production function 生产函数 links inputs to output. In the short run 短期 at least one input (usually capital) is fixed 固定; in the long run 长期 all inputs vary.

Total product 总产量 is the total output.
Marginal product 边际产量 (MP) is the extra output from one more unit of a variable input (usually labor): $MP=\dfrac{\Delta\ \text{output}}{\Delta\ \text{labor}}$.
Average product 平均产量 is output per worker.

As you add workers to fixed capital, MP eventually falls – the law of diminishing marginal returns 边际收益递减法则. This shape of MP is what drives the shape of the cost curves below.

A robotic arm working on a factory production line — The production function turns inputs — labour and capital like this robot — into output

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
production function/prəˈdʌkʃn ˈfʌŋkʃn/	fungsi produksi
short run/ʃɔːt rʌn/	jangka pendek
fixed/fɪkst/	tetap
long run/lɒŋ rʌn/	jangka panjang
Total product/ˈtəʊtl ˈprɒdʌkt/	Produk total
Marginal product/ˈmɑːdʒɪnl ˈprɒdʌkt/	Produk marjinal
Average product/ˈævrɪdʒ ˈprɒdʌkt/	Produk rata-rata
law of diminishing marginal returns/lɔː ɒv dɪˈmɪnɪʃɪŋ ˈmɑːdʒɪnl rɪˈtɜːnz/	hukum hasil marginal menurun

3.2

Short-Run Production Costs

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-1): Firms' production and cost constraints over different input and output levels shape optimal decisions in the short run and long run.

PRD-1.A.4 Fixed costs and variable costs determine the total cost.
PRD-1.A.5 Marginal cost, average (fixed, variable, and total) cost, total cost, and total variable cost change as total output changes, but total fixed cost remains constant at all output levels, including zero output.
PRD-1.A.6 Production functions with diminishing marginal returns yield an upward-sloping marginal cost curve.
PRD-1.A.7 Specialization and the division of labor reduce marginal costs for firms.
PRD-1.A.8 Cost curves can shift in response to changes in input costs and productivity.

Bahasa Indonesia

Pemahaman Abadi (PRD-1): Kendala produksi dan biaya perusahaan pada berbagai tingkat input dan output membentuk keputusan optimal dalam jangka pendek dan jangka panjang.

PRD-1.A.4 Biaya tetap dan biaya variabel menentukan total biaya.
PRD-1.A.5 Biaya marjinal, biaya rata-rata (tetap, variabel, dan total), total biaya, dan total biaya variabel berubah seiring perubahan total output, tetapi total biaya tetap tidak berubah pada semua tingkat output, termasuk nol output.
PRD-1.A.6 Fungsi produksi dengan hasil marjinal yang semakin menurun menghasilkan kurva biaya marjinal yang menanjak.
PRD-1.A.7 Spesialisasi dan pembagian kerja menurunkan biaya marjinal bagi perusahaan.
PRD-1.A.8 Kurva biaya dapat bergeser sebagai respons terhadap perubahan biaya input dan produktivitas.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Short-run cost curves (MC, ATC, AVC)

Costs split into fixed and variable:

The short-run marginal, average, and average variable cost curves

Fixed cost 固定成本 (FC) does not change with output (rent on the factory).
Variable cost 可变成本 (VC) rises with output (materials, labor).
Total cost 总成本 $TC=FC+VC$.

The per-unit costs matter most:

Average fixed cost $AFC=FC/Q$ falls continuously (spreading fixed cost).
Average variable cost $AVC=VC/Q$ and average total cost $ATC=TC/Q$ are U-shaped.
Marginal cost 边际成本 $MC=\dfrac{\Delta TC}{\Delta Q}$ is the cost of one more unit.

Two key facts: MC is the mirror image of MP (when MP rises, MC falls, and vice versa), and MC cuts both AVC and ATC at their minimum points (when marginal is below average, the average falls; when above, it rises).

Worked example. A firm has fixed cost $FC=\$100$. At $Q=10$ its total cost is $\$300$, so variable cost is $\$200$: then $ATC=\tfrac{300}{10}=\$30$, $AVC=\tfrac{200}{10}=\$20$, and $AFC=\tfrac{100}{10}=\$10$ (note $AFC+AVC=ATC$). If raising output to $Q=11$ pushes total cost to $\$325$, the marginal cost of that $11$th unit is $\dfrac{\Delta TC}{\Delta Q}=\dfrac{325-300}{1}=\$25$.

Explore · ⁨Jelajahi⁩

Explore the U-shaped cost curves · ⁨Jelajahi kurva biaya berbentuk U⁩

As output rises, marginal cost eventually climbs (diminishing returns) and cuts through the U-shaped average cost at its minimum — the most efficient scale. · ⁨Saat output naik, biaya marginal akhirnya meningkat (pengembalian yang semakin berkurang) dan memotong biaya rata-rata yang berbentuk U di titik minimumnya — skala paling efisien.⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
Fixed cost/fɪkst kɒst/	Kos tetap
Variable cost/ˈveərɪəbl kɒst/	Biaya variabel
Total cost/ˈtəʊtl kɒst/	Kos keseluruhan
Marginal cost/ˈmɑːdʒɪnl kɒst/	Biaya marginal

3.3

Long-Run Production Costs

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-1): Firms' production and cost constraints over different input and output levels shape optimal decisions in the short run and long run.

PRD-1.A.9 In the long run, firms can adjust all their inputs, and as a result, all costs become variable.
PRD-1.A.10 The relationship between inputs and outputs in the long run is described by the scale of production—increasing, decreasing, or constant returns to scale.
PRD-1.A.11 The long-run average total cost is characterized by economies of scale, diseconomies of scale, or constant returns to scale (efficient scale).
PRD-1.A.12 The minimum efficient scale plays a role in determining the concentration of firms in a market and the market structure.

Bahasa Indonesia

Pemahaman Abadi (PRD-1): Kendala produksi dan biaya perusahaan pada berbagai tingkat input dan output membentuk keputusan optimal dalam jangka pendek dan jangka panjang.

PRD-1.A.9 Dalam jangka panjang, perusahaan dapat menyesuaikan semua input mereka, sehingga semua biaya menjadi variabel.
PRD-1.A.10 Hubungan antara input dan output dalam jangka panjang dijelaskan oleh skala produksi—pengembalian skala meningkat, menurun, atau konstan.
PRD-1.A.11 Total biaya rata-rata jangka panjang dikarakteristikkan oleh ekonomi skala, disekonomi skala, atau pengembalian skala konstan (skala efisien).
PRD-1.A.12 Skala efisien minimum berperan dalam menentukan konsentrasi perusahaan di pasar dan struktur pasar.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

In the long run all inputs – including plant size – can change, so only the long-run average total cost (LRATC) curve matters. Its shape shows returns to scale:

Economies and diseconomies of scale on the long-run average cost curve

Economies of scale 规模经济: LRATC falls as output grows (bulk buying, specialization).
Constant returns to scale: LRATC flat.
Diseconomies of scale 规模不经济: LRATC rises (a firm too big to manage well).

Exam skill: know that "diminishing returns" is a short-run idea (one fixed input) while "economies of scale" is a long-run idea (all inputs vary) – examiners test the distinction.

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
Economies of scale/ɪˈkɒnəmiz ɒv skeɪl/	Ekonomi skala
Diseconomies of scale/ˌdɪsɪˈkɒnəmiz ɒv skeɪl/	Diseconomies of scale

3.4

Types of Profit

Syllabus · ⁨Silabus⁩

English

Learning Objective CBA-2.C: a. Define the different types of profit. b. Explain how firms respond to profit opportunities. c. Calculate a firm's profit or loss.

CBA-2.C.1 Firms respond to economic profit (loss) rather than accounting profit.
CBA-2.C.2 Accounting profit fails to account for implicit costs (such as cost of financial capital, compensation for risk, or an entrepreneur's time), which, if fully compensated, result in normal profit.

Bahasa Indonesia

Tujuan Pembelajaran CBA-2.C: a. Definisikan berbagai jenis laba. b. Jelaskan bagaimana perusahaan merespons peluang laba. c. Hitung laba atau rugi sebuah perusahaan.

CBA-2.C.1 Perusahaan merespons laba (rugi) ekonomi daripada laba akuntansi.
CBA-2.C.2 Laba akuntansi tidak memperhitungkan biaya implisit (seperti biaya modal keuangan, kompensasi risiko, atau waktu seorang wirausaha), yang jika dikompensasi sepenuhnya, akan menghasilkan laba normal.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Economists count all opportunity costs, including the owner's:

Explicit costs 显性成本 are out-of-pocket payments; implicit costs 隐性成本 are the opportunity costs of owner-supplied resources (forgone salary, forgone interest).
Accounting profit 会计利润 $=$ revenue $-$ explicit costs.
Economic profit 经济利润 $=$ revenue $-$ explicit $-$ implicit costs.

Because economic profit subtracts more, it is smaller. Zero economic profit (a normal profit 正常利润) still means the owner is earning exactly the opportunity cost of their resources – a perfectly acceptable outcome.

Worked example. A shopkeeper takes in $\$200{,}000$ of revenue and pays $\$120{,}000$ in explicit costs, so accounting profit is $\$80{,}000$. But she gave up a $\$70{,}000$ salary elsewhere and $\$5{,}000$ of interest on the savings she invested – $\$75{,}000$ of implicit costs. Her economic profit is $80{,}000-75{,}000=\$5{,}000$: still positive, so staying in business genuinely beats her next-best alternative.

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
Explicit costs/ekˈsplɪsɪt kɒsts/	Biaya eksplisit
implicit costs/ɪmˈplɪsɪt kɒsts/	biaya implisit
Accounting profit/əˈkaʊntɪŋ ˈprɒfɪt/	Laba akuntansi
Economic profit/ˌiːkəˈnɒmɪk ˈprɒfɪt/	Laba ekonomi
normal profit/ˈnɔːml ˈprɒfɪt/	keuntungan normal

3.5

Profit Maximization

Syllabus · ⁨Silabus⁩

English

Learning Objective CBA-2.D: a. Define (using graphs or data as appropriate) the profit-maximizing rule. b. Explain (using a graph or data as appropriate) the profit-maximizing level of production.

CBA-2.D.1 Firms are assumed to produce output to maximize their profits by comparing marginal revenue and marginal cost.

Bahasa Indonesia

Tujuan Pembelajaran CBA-2.D: a. Definisikan (menggunakan grafik atau data jika sesuai) aturan maksimisasi laba. b. Jelaskan (menggunakan grafik atau data jika sesuai) tingkat produksi yang memaksimumkan laba.

CBA-2.D.1 Diasumsikan bahwa perusahaan memproduksi output untuk memaksimumkan labanya dengan membandingkan pendapatan marjinal dan biaya marjinal.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Every firm, in every market structure, maximizes profit at the quantity where marginal revenue equals marginal cost:

$$MR=MC.$$

Produce each unit whose MR exceeds its MC; stop when they are equal. Producing less leaves profitable units unmade; producing more adds units that cost more than they earn.

3.6

Deciding to Produce, Enter, or Exit

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-2): Firms' short-run decisions to produce output, and long-run decisions to enter or exit a market, are based on profitability.

Learning Objective PRD-2.A: Explain (using graphs or data where appropriate) firms' short-run decisions to produce positive output levels, or long-run decisions to enter or exit a market in response to profit-making opportunities.

PRD-2.A.1 In the short run, firms decide to operate (i.e., produce positive output) or shut down (i.e., produce zero output) by comparing total revenue to total variable cost or price to average variable cost (AVC).
PRD-2.A.2 In the absence of barriers to entry or exit, in the long run (i.e., once factors that are fixed in the short run become variable), firms enter a market in which there are profit-making opportunities and exit a market when they anticipate economic losses.

Bahasa Indonesia

Pemahaman Abadi (PRD-2): Keputusan jangka pendek perusahaan untuk memproduksi output, serta keputusan jangka panjang untuk masuk atau keluar pasar, didasarkan pada profitabilitas.

Tujuan Pembelajaran PRD-2.A: Jelaskan (menggunakan grafik atau data jika sesuai) keputusan jangka pendek perusahaan untuk memproduksi tingkat output positif, atau keputusan jangka panjang untuk masuk atau keluar pasar sebagai respons terhadap peluang keuntungan.

PRD-2.A.1 Dalam jangka pendek, perusahaan memutuskan untuk beroperasi (yaitu, memproduksi output positif) atau menutup operasi (yaitu, memproduksi nol output) dengan membandingkan total pendapatan dengan total biaya variabel atau harga dengan biaya rata-rata variabel (AVC).
PRD-2.A.2 Tidak adanya hambatan masuk atau keluar, dalam jangka panjang (yaitu, setelah faktor-faktor yang tetap dalam jangka pendek menjadi variabel), perusahaan memasuki pasar yang menawarkan peluang keuntungan dan keluar dari pasar saat mereka mengantisipasi kerugian ekonomi.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Even at $MR=MC$, a firm must check whether to operate:

Short run – the shutdown rule: keep producing only if price covers average variable cost ($P\geq AVC$). If $P, shut down and lose only fixed cost. So the firm's short-run supply curve is its MC curve above minimum AVC.
Profit check: compare $P$ to $ATC$ at the profit-maximizing quantity – $P>ATC$ means economic profit, $P means a loss, $P=ATC$ means break-even.
Long run – entry and exit: economic profits attract entry 进入; losses cause exit 退出. This continues until economic profit is zero.

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
entry/ˈentri/	masuk
exit/ˈeɡzɪt/	keluar

3.7

Perfect Competition

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-3): Even with a common goal of profit-maximization, market structure constrains and influences prices, output, and efficiency.

Learning Objective PRD-3.A: a. Define (using graphs as appropriate) the characteristics of perfectly competitive markets and efficiency. b. Explain (using graphs where appropriate) equilibrium and firm decision making in perfectly competitive markets and how prices in perfectly competitive markets lead to efficient outcomes. c. Calculate (using data from a graph or table as appropriate) economic profit (loss) in perfectly competitive markets.

PRD-3.A.1 A perfectly competitive market is efficient. Firms in perfectly competitive markets face no barriers to entry and have no market power.
PRD-3.A.2 In perfectly competitive markets, prices communicate to consumers and producers the magnitude of others' marginal costs of production and marginal benefits of consumption and provide incentives to act on that information (i.e., price equals marginal cost in an efficient market).
PRD-3.A.3 In perfectly competitive markets, firms can sell all their outputs at a constant price determined by the market.
PRD-3.A.4 At a competitive market equilibrium, firms are price takers and select output to maximize profit by producing the level of output where the marginal cost equals marginal revenue (at the price).
PRD-3.A.5 At a competitive market equilibrium, the price of a product equals both the private marginal benefit received by the last unit consumed and the private marginal cost incurred to produce the last unit, thus achieving allocative efficiency.
PRD-3.A.6 In a short-run competitive equilibrium, price can either be above or below its long-run competitive level resulting in profits or losses, motivating entry or exit of firms and moving prices and quantities toward long-run equilibrium.
PRD-3.A.7 In a long-run perfectly competitive equilibrium, productive efficiency implies all operating firms produce at efficient scale, price equals marginal cost and minimum average total cost, and firms earn zero economic profit.
PRD-3.A.8 Firms may be in a constant cost, increasing cost, or decreasing cost industry. Long-run prices depend on the portion of the long-run cost curves on which firms operate.
PRD-3.A.9 A perfectly competitive market in long-run equilibrium is allocatively and productively efficient.

Bahasa Indonesia

Pemahaman Abadi (PRD-3): Bahkan dengan tujuan bersama untuk memaksimumkan laba, struktur pasar membatasi dan mempengaruhi harga, output, dan efisiensi.

Tujuan Pembelajaran PRD-3.A: a. Definisikan (menggunakan grafik jika sesuai) karakteristik pasar persaingan sempurna dan efisiensi. b. Jelaskan (menggunakan grafik jika sesuai) keseimbangan dan pengambilan keputusan perusahaan dalam pasar persaingan sempurna serta bagaimana harga dalam pasar persaingan sempurna mengarah pada hasil yang efisien. c. Hitung (menggunakan data dari grafik atau tabel jika sesuai) laba (rugi) ekonomi dalam pasar persaingan sempurna.

PRD-3.A.1 Pasar persaingan sempurna itu efisien. Perusahaan dalam pasar persaingan sempurna tidak menghadapi hambatan masuk dan tidak memiliki kekuatan pasar.
PRD-3.A.2 Dalam pasar persaingan sempurna, harga mengomunikasikan kepada konsumen dan produsen besaran biaya produksi marjinal orang lain dan manfaat konsumsi marjinal, serta memberikan insentif untuk bertindak berdasarkan informasi tersebut (yaitu, harga sama dengan biaya marjinal dalam pasar yang efisien).
PRD-3.A.3 Dalam pasar persaingan sempurna, perusahaan dapat menjual seluruh output mereka pada harga konstan yang ditentukan oleh pasar.
PRD-3.A.4 Pada keseimbangan pasar kompetitif, perusahaan adalah penerima harga dan memilih output untuk memaksimumkan laba dengan memproduksi tingkat output di mana biaya marjinal sama dengan pendapatan marjinal (pada harga tersebut).
PRD-3.A.5 Pada keseimbangan pasar kompetitif, harga suatu produk sama dengan manfaat marjinal pribadi yang diterima dari unit terakhir yang dikonsumsi dan biaya marjinal pribadi yang ditanggung untuk memproduksi unit terakhir, sehingga mencapai efisiensi alokasi.
PRD-3.A.6 Dalam keseimbangan kompetitif jangka pendek, harga dapat berada di atas atau di bawah tingkat kompetitif jangka panjangnya, menghasilkan keuntungan atau kerugian, yang memotivasi masuk atau keluarnya perusahaan dan menggerakkan harga serta kuantitas menuju keseimbangan jangka panjang.
PRD-3.A.7 Dalam keseimbangan persaingan sempurna jangka panjang, efisiensi produktif menyiratkan bahwa semua perusahaan yang beroperasi berproduksi pada skala efisien, harga sama dengan biaya marjinal dan minimum rata-rata total biaya, dan perusahaan mendapatkan nol profit ekonomi.
PRD-3.A.8 Perusahaan dapat berada dalam industri biaya konstan, biaya meningkat, atau biaya menurun. Harga jangka panjang bergantung pada bagian kurva biaya jangka panjang di mana perusahaan beroperasi.
PRD-3.A.9 Pasar yang bersaing sempurna dalam keseimbangan jangka panjang bersifat efisien secara alokatif dan produktif.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

A perfectly competitive 完全竞争 market has many small firms, an identical (homogeneous) product, free entry and exit, and perfect information. Each firm is a price taker 价格接受者 – too small to affect the price – so it faces a horizontal demand curve at the market price, and price = marginal revenue = average revenue ($P=MR=AR$).

This is why economists prize perfect competition. In long-run equilibrium it is both allocatively efficient 配置效率 and productively efficient 生产效率. Allocative efficiency holds because the firm produces where $P = MC$: the price (society's marginal benefit from the last unit) equals its marginal cost, so exactly the right amount is made. Productive efficiency holds because free entry drives price down to the minimum of average total cost, so goods are made as cheaply as possible. The market price is itself a signal that communicates everyone's marginal costs and benefits.

The market sets the price; the price-taking firm produces where MC = P, here with short-run profit

The side-by-side panel is the graph the exam wants: the market (left) fixes the price $P^{*}$; the firm (right) takes it as a horizontal line and produces where $MC=P$. When $P>ATC$ there is a short-run profit (the shaded box); that profit attracts entry, which shifts market supply right and pushes the price down.

A perfectly competitive firm makes only normal profit in the long run

Short run: the firm can earn profit, break even, or take a loss, producing where $P=MC$.
Long run: entry and exit drive the firm to zero economic profit, producing where $P=MC=ATC$ at minimum ATC. This double efficiency – productive efficiency (lowest-cost output) and allocative efficiency ($P=MC$, so the last unit's value equals its cost) – is the benchmark against which every other market structure is judged.

Exam skill: be able to draw the side-by-side market and single-firm graphs, show a short-run profit or loss, then show how entry/exit restores long-run equilibrium at minimum ATC.

Explore · ⁨Jelajahi⁩

A price-taking firm in a competitive market · ⁨Perusahaan yang menerima harga dalam pasar kompetitif⁩

In perfect competition the market sets the price and each firm is a price-taker. It produces where price equals marginal cost, earning zero economic profit in the long run. · ⁨Dalam persaingan sempurna, pasar menetapkan harga dan setiap perusahaan adalah penerima harga. Perusahaan memproduksi di mana harga sama dengan biaya marginal, memperoleh nol laba ekonomi dalam jangka panjang.⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
perfectly competitive/ˈpɜːfektlɪ kəmˈpetɪtɪv/	Persaingan sempurna
price taker/praɪs ˈteɪkə/	penerima harga
allocatively efficient/ˈæləkətɪvli ɪˈfɪʃənt/	efisien alokatif
productively efficient/prəˈdʌktɪvli ɪˈfɪʃənt/	Efisien secara produktif

3.7

Exam tips

Know the cost curves: AFC falls, ATC/AVC are U-shaped, and MC cuts ATC and AVC at their minimums.
Every firm maximises profit at MR = MC; check the shutdown rule ($P \ge AVC$ in the short run).
Distinguish accounting profit (revenue − explicit costs) from economic profit (also minus implicit/opportunity costs); zero economic profit is normal.
"Diminishing returns" is short-run (one fixed input); "economies of scale" is long-run (all inputs vary).
In perfect competition $P=MR=AR$; entry/exit drive long-run economic profit to zero at minimum ATC.

Imperfect Competition · ⁨Persaingan Tidak Sempurna⁩

Watch lesson · ⁨Tonton pelajaran⁩

Open this topic on its own page · ⁨Buka topik ini di halaman sendiri⁩

4.1

Imperfect Competition and Market Power · ⁨Persaingan Tidak Sempurna dan Kekuatan Pasar⁩

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-3): Even with a common goal of profit-maximization, market structure constrains and influences prices, output, and efficiency.

Learning Objective PRD-3.B: a. Define (using graphs where appropriate) the characteristics of imperfectly competitive markets and inefficiency.

PRD-3.B.1 Imperfectly competitive markets include monopoly, oligopoly, and monopolistic competition in product markets and monopsony in factor markets.
PRD-3.B.2 In imperfectly competitive output markets and assuming all else is constant, a firm must lower price to sell additional units.
PRD-3.B.3 In imperfectly competitive markets, consumers and producers respond to prices that are above the marginal costs of production and/or marginal benefits of consumption (i.e., price is greater than marginal cost in an inefficient market).
PRD-3.B.4 Incentives to enter an industry may be mitigated by barriers to entry. Barriers to entry—such as high fixed/start-up costs, legal barriers to entry, and exclusive ownership of key resources—can sustain imperfectly competitive market structures.

Bahasa Indonesia

Pemahaman Abadi (PRD-3): Bahkan dengan tujuan bersama untuk memaksimumkan laba, struktur pasar membatasi dan mempengaruhi harga, output, dan efisiensi.

Tujuan Pembelajaran PRD-3.B: a. Definisikan (menggunakan grafik jika sesuai) karakteristik pasar tidak kompetitif sempurna dan ketidakefisienan.

PRD-3.B.1 Pasar tidak kompetitif sempurna mencakup monopoli, oligopoli, dan persaingan monopolistik dalam pasar produk, serta monopsoni dalam pasar faktor.
PRD-3.B.2 Dalam pasar output tidak kompetitif sempurna dan dengan asumsi hal lain tetap, perusahaan harus menurunkan harga untuk menjual unit tambahan.
PRD-3.B.3 Dalam pasar tidak kompetitif sempurna, konsumen dan produsen merespons harga yang berada di atas biaya marjinal produksi dan/atau manfaat marjinal konsumsi (yaitu, harga lebih besar daripada biaya marjinal dalam pasar yang tidak efisien).
PRD-3.B.4 Insentif untuk memasuki industri dapat diredam oleh hambatan masuk. Hambatan masuk—seperti biaya tetap/mulai yang tinggi, hambatan hukum masuk, dan kepemilikan eksklusif sumber daya kunci—dapat mempertahankan struktur pasar tidak kompetitif sempurna.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

English

Most real markets are imperfectly competitive 不完全竞争: firms have some market power 市场势力 – the ability to set price rather than take it. The source of that power is a downward-sloping demand curve facing the firm, which means that to sell one more unit the firm must lower the price on all units.

Because of this, marginal revenue is below price ($MR) for every firm with market power. On a straight-line demand curve the MR curve has the same intercept but twice the slope, lying below demand. This one fact – $MR – separates every imperfect market from perfect competition and explains why they produce less and charge more.

Worked example. A firm with market power faces demand $P=100-Q$. Selling $1$ unit gives $P=\$99$ and total revenue $\$99$; selling a $2$nd forces the price down to $\$98$ on both units, so revenue rises to $2\times98=\$196$. The marginal revenue of that $2$nd unit is $196-99=\$97$ – below its $\$98$ price. In general $MR=100-2Q$, falling twice as fast as demand.

Bahasa Indonesia

Garis perakitan mobil: kekuatan pasar dan skala perusahaan berbeda di bawah persaingan tidak sempurna

Sebagian besar pasar nyata bersifat persaingan tidak sempurna: perusahaan memiliki beberapa kekuatan pasar – kemampuan untuk menetapkan harga alih-alih menerimanya. Sumber kekuatan tersebut adalah kurva permintaan yang miring ke bawah yang dihadapi perusahaan, yang berarti untuk menjual satu unit lagi, perusahaan harus menurunkan harga untuk semua unit.

Struktur pasar berkisar dari persaingan sempurna hingga monopoli

Oleh karena itu, pemasukan marjinal lebih rendah dari harga ($MR) untuk setiap perusahaan yang memiliki kekuatan pasar. Pada kurva permintaan garis lurus, kurva MR memiliki titik potong yang sama tetapi kemiringan dua kali lipat, berada di bawah kurva permintaan. Fakta tunggal ini – $MR – memisahkan setiap pasar tidak sempurna dari persaingan sempurna dan menjelaskan mengapa mereka memproduksi lebih sedikit dan memungut harga lebih tinggi.

Contoh terpecahkan. Sebuah perusahaan dengan kekuatan pasar menghadapi permintaan $P=100-Q$. Menjual $1$ unit menghasilkan $P=\$99$ and total revenue $\$99$; menjual unit ke-$2$ memaksa harga turun menjadi $\$98$ on both units, so revenue rises to $2\times98=\$196$. Pemasukan marjinal dari unit ke-$2$ tersebut adalah $196-99=\$97$ – below its $\$98$ harga. Secara umum $MR=100-2Q$, turun dua kali lebih cepat daripada kurva permintaan.

4.2

Monopoly · ⁨Monopoli⁩

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-3): Even with a common goal of profit-maximization, market structure constrains and influences prices, output, and efficiency.

Learning Objective PRD-3.B: b. Explain (using graphs where appropriate) equilibrium, firm decision making, consumer surplus, producer surplus, profit (loss), and deadweight loss in imperfectly competitive markets and why prices in imperfectly competitive markets cannot be relied on to coordinate the actions of all possible market participants and can lead to inefficient outputs. c. Calculate (using data from a graph or table as appropriate) areas of consumer surplus, producer surplus, profit (loss), and deadweight loss in imperfectly competitive markets.

PRD-3.B.5 A monopoly exists because of barriers to entry.
PRD-3.B.6 In a monopoly, equilibrium (profit-maximizing) quantity is determined by equating marginal revenue (MR) to marginal cost (MC). The price charged is greater than the marginal cost.
- Equation: $MR = MC$
PRD-3.B.7 In a natural monopoly, long-run economies of scale for a single firm exist throughout the entire effective demand of its product.

Bahasa Indonesia

Pemahaman Abadi (PRD-3): Bahkan dengan tujuan bersama untuk memaksimumkan laba, struktur pasar membatasi dan mempengaruhi harga, output, dan efisiensi.

Tujuan Pembelajaran PRD-3.B: b. Jelaskan (menggunakan grafik jika sesuai) keseimbangan, pengambilan keputusan perusahaan, surplus konsumen, surplus produsen, profit (rugi), dan hilangnya beban mati dalam pasar tidak kompetitif sempurna dan mengapa harga dalam pasar tidak kompetitif sempurna tidak dapat diandalkan untuk mengoordinasikan tindakan semua peserta pasar yang mungkin dan dapat mengarah pada output yang tidak efisien. c. Hitung (menggunakan data dari grafik atau tabel jika sesuai) area surplus konsumen, surplus produsen, profit (rugi), dan hilangnya beban mati dalam pasar tidak kompetitif sempurna.

PRD-3.B.5 Monopoli ada karena adanya hambatan masuk.
PRD-3.B.6 Dalam monopoli, kuantitas keseimbangan (memaksimalkan profit) ditentukan dengan menyamakan pendapatan marjinal (MR) dengan biaya marjinal (MC). Harga yang dikenakan lebih besar daripada biaya marjinal.
- Persamaan: $MR = MC$
PRD-3.B.7 Dalam monopoli alami, penghematan skala jangka panjang untuk satu perusahaan terdapat di seluruh permintaan efektif produknya.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

English

Monopoly: MR = MC pricing

A monopoly 垄断 is a single seller of a product with no close substitutes, protected by barriers to entry 进入壁垒 (economies of scale – a natural monopoly 自然垄断 – control of a key resource, patents, or government license).

The monopolist maximizes profit at $MR=MC$, then charges the highest price the demand curve allows at that quantity (read price up to the demand curve, not the MR curve).
Compared with perfect competition it produces less and charges more, earning long-run economic profit because entry is blocked.
This under-production creates deadweight loss 无谓损失 – the monopoly is allocatively inefficient because $P>MC$: the last unit is worth more than it costs, yet is not made.

Governments may respond with antitrust 反垄断 law, or regulate a natural monopoly's price toward $P=MC$ (socially optimal, but may cause a loss) or $P=ATC$ (fair-return, break-even).

Exam skill: the monopoly graph is a staple – show quantity at $MR=MC$, price up on the demand curve, and shade profit (between $P$ and $ATC$) and deadweight loss (the triangle to the competitive quantity).

Bahasa Indonesia

Monopoli: Penetapan harga MR = MC

Sebuah monopoli adalah penjual tunggal produk tanpa pengganti dekat, dilindungi oleh hambatan masuk (skala ekonomi – monopoli alami – penguasaan sumber daya kunci, paten, atau lisensi pemerintah).

Monopoli memaksimalkan laba di mana MC = MR dan dapat memperoleh laba supernormal

Monopolis memaksimalkan laba pada $MR=MC$, kemudian menetapkan harga tertinggi yang memungkinkan oleh kurva permintaan pada kuantitas tersebut (baca harga naik ke kurva permintaan, bukan kurva MR).
Dibandingkan dengan persaingan sempurna, ia memproduksi lebih sedikit dan memungut harga lebih tinggi, memperoleh laba ekonomi jangka panjang karena masuk diblokir.
Produksi yang kurang ini menciptakan kerugian deadweight; monopoli bersifat inefisien alokatif karena $P>MC$: unit terakhir bernilai lebih tinggi daripada biayanya, namun tidak diproduksi.

Pemerintah mungkin merespons dengan hukum antitrust, atau mengatur harga monopoli alami menuju $P=MC$ (optimal secara sosial, tetapi dapat menyebabkan kerugian) atau $P=ATC$ (pengembalian adil, impas).

Keterampilan ujian: grafik monopoli adalah hal standar – tunjukkan kuantitas pada $MR=MC$, harga naik pada kurva permintaan, dan arsir area laba (antara $P$ dan $ATC$) serta kerugian mati (segitiga menuju kuantitas kompetitif).

Pabrik utilitas besar: monopoli dan kekuatan pasar berarti satu perusahaan dapat menetapkan harga di atas biaya marjinal

Explore · ⁨Jelajahi⁩

A monopoly's cost curves · ⁨Kurva biaya monopoli⁩

A monopoly is the sole seller, so it faces the whole downward demand curve and its marginal revenue lies below price. It produces where MR = MC — less output, higher price than competition. · ⁨Monopoli adalah satu-satunya penjual, sehingga ia menghadapi seluruh kurva permintaan yang menurun dan pendapatan marginalnya berada di bawah harga. Ia memproduksi di mana MR = MC — output lebih sedikit, harga lebih tinggi dibanding persaingan.⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
imperfectly competitive/ɪmˈpɜːfektlɪ kəmˈpetɪtɪv/	Persaingan tidak sempurna
market power/ˈmɑːkɪt ˈpaʊə/	kekuatan pasar
monopoly/məˈnɒpəli/	monopoli
barriers to entry/ˈbærɪəz tʊ ˈentri/	hambatan masuk
natural monopoly/ˈnætʃərəl məˈnɒpəli/	monopoli alami
deadweight loss/ˈdedweɪt lɒs/	kerugian berat mati
antitrust/ˌæntɪˈtrʌst/	antitrust
Price discrimination/praɪs dɪˌskrɪmɪˈneɪʃn/	Diskriminasi harga
Monopolistic competition/məˈnɒpəlɪstɪk ˌkɒmpəˈtɪʃn/	Persaingan monopolistik
differentiated/ˌdɪfəˈrenʃɪeɪtɪd/	terdiferensiasi
excess capacity/ekˈses kəˈpæsɪti/	kapasitas berlebih
oligopoly/ˌɒlɪˈɡɒpəli/	oligopoli
interdependent/ˌɪntədɪˈpendənt/	Saling ketergantungan
game theory/ɡeɪm ˈθɪəri/	teori permainan

4.3

Price Discrimination · ⁨Diskriminasi Harga⁩

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-3): Even with a common goal of profit-maximization, market structure constrains and influences prices, output, and efficiency.

PRD-3.B.8 A firm with market power can engage in price discrimination to increase its profits or capture additional consumer surplus under certain conditions.
PRD-3.B.9 With perfect price discrimination, a monopolist produces the quantity where price equals marginal cost (just as a competitive market would) but extracts all economic surplus associated with its product and eliminates all deadweight loss.
- Equation: $P = MC$

Bahasa Indonesia

Pemahaman Abadi (PRD-3): Bahkan dengan tujuan bersama untuk memaksimumkan laba, struktur pasar membatasi dan mempengaruhi harga, output, dan efisiensi.

PRD-3.B.8 Perusahaan dengan kekuatan pasar dapat melakukan diskriminasi harga untuk meningkatkan profitnya atau menangkap surplus konsumen tambahan di bawah kondisi tertentu.
PRD-3.B.9 Dengan diskriminasi harga sempurna, seorang monopoli memproduksi kuantitas di mana harga sama dengan biaya marjinal (sama seperti pasar kompetitif) tetapi mengekstrak semua surplus ekonomi yang terkait dengan produknya dan menghilangkan semua hilangnya beban mati.
- Persamaan: $P = MC$

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

English

Price discrimination 价格歧视 is charging different buyers different prices for the same good. It requires market power, the ability to separate buyers by willingness to pay, and the ability to prevent resale.

Under perfect (first-degree) price discrimination, the firm charges each buyer their maximum price. The result: the firm produces the efficient quantity (where $P=MC$, no deadweight loss), but converts all consumer surplus into producer surplus (profit). Real examples – student discounts, airline fares, coupons – are partial versions.

Bahasa Indonesia

Diskriminasi harga adalah memungut harga berbeda dari pembeli yang berbeda untuk barang yang sama. Hal ini memerlukan kekuatan pasar, kemampuan untuk memisahkan pembeli berdasarkan kemauan membayar, dan kemampuan untuk mencegah penjualan kembali.

Di bawah diskriminasi harga sempurna (derajat pertama), perusahaan memungut harga maksimum dari setiap pembeli. Hasilnya: perusahaan memproduksi kuantitas efisien (di mana $P=MC$, tidak ada kerugian mati), tetapi mengubah seluruh surplus konsumen menjadi surplus produsen (laba). Contoh nyata – diskon mahasiswa, tarif penerbangan, kupon – adalah versi parsial.

Explore · ⁨Jelajahi⁩

Elasticity and price discrimination · ⁨Elastisitas dan pembedaan harga⁩

Price discrimination charges each group a different price by their elasticity: inelastic buyers (who won't switch) pay more, elastic buyers pay less. Stretch the curve to see why. · ⁨Pembedaan harga menagih kelompok berbeda harga berdasarkan elastisitas-nya: pembeli inelastis (yang tidak akan beralih) membayar lebih, pembeli elastis membayar lebih sedikit. Tarik kurva untuk melihat alasannya.⁩

4.4

Monopolistic Competition · ⁨Persaingan Monopolistik⁩

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-3): Even with a common goal of profit-maximization, market structure constrains and influences prices, output, and efficiency.

PRD-3.B.10 In a market with monopolistic competition, firms producing differentiated products may earn positive, negative, or zero economic profit in the short run. Firms typically use advertising as a means of differentiating their product. Free entry and exit drive profits to zero in the long run. The output level, however, is smaller than the output level needed to minimize average total costs, creating excess capacity. The price is greater than marginal cost, creating allocative inefficiency.

Bahasa Indonesia

Pemahaman Abadi (PRD-3): Bahkan dengan tujuan bersama untuk memaksimumkan laba, struktur pasar membatasi dan mempengaruhi harga, output, dan efisiensi.

PRD-3.B.10 Dalam pasar dengan persaingan monopolistik, perusahaan yang memproduksi produk terdiferensiasi dapat memperoleh profit ekonomi positif, negatif, atau nol dalam jangka pendek. Perusahaan biasanya menggunakan iklan sebagai sarana untuk mendiferensiasikan produknya. Masuk dan keluar bebas mendorong profit menjadi nol dalam jangka panjang. Namun, tingkat output lebih kecil daripada tingkat output yang diperlukan untuk meminimalkan biaya rata-rata total, menciptakan kapasitas berlebih. Harga lebih besar daripada biaya marjinal, menciptakan inefisiensi alokasi.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

English

Monopolistic competition 垄断竞争 has many firms selling differentiated 差异化 products with easy entry and exit (restaurants, salons, clothing brands). Product differentiation gives each firm a downward-sloping demand curve and thus some price-setting power.

Short run: like a monopoly – produce at $MR=MC$, and profit or loss is possible.
Long run: easy entry competes away profit, so each firm earns zero economic profit, producing where demand is tangent to ATC.
Because it still charges $P>MC$ and does not produce at minimum ATC, it has excess capacity 过剩产能 and is neither allocatively nor productively efficient. The trade-off society accepts is product variety and choice.

Bahasa Indonesia

Persaingan monopolistik memiliki banyak perusahaan yang menjual produk terdiferensiasi dengan masuk dan keluar yang mudah (restoran, salon, merek pakaian). Diferensiasi produk memberikan setiap perusahaan kurva permintaan miring ke bawah dan karenanya beberapa kekuatan penetapan harga.

Jangka pendek: seperti monopoli – produksi pada $MR=MC$, dan laba atau rugi dimungkinkan.
Jangka panjang: masuk yang mudah bersaing menghilangkan laba, sehingga setiap perusahaan memperoleh laba ekonomi nol, memproduksi di mana kurva permintaan bersinggungan dengan ATC.
Karena masih memungut $P>MC$ dan tidak memproduksi pada ATC minimum, perusahaan memiliki kapasitas berlebih dan tidak efisien secara alokatif maupun produktif. Trade-off yang diterima masyarakat adalah variasi produk dan pilihan.

4.5

Oligopoly and Game Theory · ⁨Oligopoli dan Teori Permainan⁩

Syllabus · ⁨Silabus⁩

Enduring Understanding	Learning Objective	Essential Knowledge
PRD-3 Even with a common goal of profit-maximization, market structure constrains and influences prices, output, and efficiency.	PRD-3.C a. Define (using tables as appropriate) key terms, strategies, and concepts relating to oligopolies and simple games. b. Explain (using tables as appropriate) strategies and equilibria in simple games and the connections to theoretical behaviors in various oligopoly market and non-market settings. c. Calculate (using tables as appropriate) the incentive sufficient to alter a player's dominant strategy.	PRD-3.C.1 An oligopoly is an inefficient market structure with high barriers to entry, where there are few firms acting interdependently. PRD-3.C.2 Firms in an oligopoly have an incentive to collude and form cartels. PRD-3.C.3 A game is a situation in which a number of individuals take actions, and the payoff for each individual depends directly on both the individual's own choice and the choices of others. PRD-3.C.4 A strategy is a complete plan of actions for playing a game; the normal form model of a game shows the payoffs that result from each collection of strategies (one for each player). PRD-3.C.5 A player has a dominant strategy when the payoff to a particular action is always higher independent of the action taken by the other player. PRD-3.C.6 A Nash equilibrium is a condition describing the set of actions in which no player can increase his or her payoff by unilaterally taking another action, given the other players' actions. Exclusion statement: Dominant strategies and Nash equilibrium with more than two players or more than two actions per player, mixed-strategy equilibria, extensive form games, and normal form games with more than two players or more than two actions per player are beyond the scope of the course and the AP Exam. PRD-3.C.7 Oligopolists have difficulty achieving the monopoly outcome for reasons similar to those that prevent players from achieving a cooperative outcome in the Prisoner's Dilemma; nevertheless, prices are generally higher and quantities lower with oligopoly (or duopoly) than with perfect competition.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

English

An oligopoly 寡头垄断 is a market with a few large, interdependent 相互依存 firms (cars, airlines, phones). Because each firm's best move depends on rivals' moves, we analyze them with game theory 博弈论.

A payoff matrix 收益矩阵 shows each firm's profit for every combination of choices.
A dominant strategy 优势策略 is a firm's best choice regardless of what the rival does.
A Nash equilibrium 纳什均衡 is an outcome where no firm can do better by unilaterally changing its choice.
The classic prisoners' dilemma 囚徒困境 shows why firms often fail to cooperate: both would gain by colluding 勾结 (acting like a monopoly), but each has an incentive to cheat, so they end up at the competitive-ish, lower-profit outcome. Collusion and cartels 卡特尔 are unstable for the same reason (and usually illegal).

Worked example. Two firms each choose a High or Low price. Profits (A, B): both High $\to(10,10)$; A Low, B High $\to(14,4)$; A High, B Low $\to(4,14)$; both Low $\to(6,6)$. For A: if B plays High, Low ($14$) beats High ($10$); if B plays Low, Low ($6$) beats High ($4$) – so Low is A's dominant strategy, and by symmetry B's too. The Nash equilibrium is both Low $(6,6)$, worse for both than the cooperative $(10,10)$ – the prisoners' dilemma in action.

Exam skill: be able to find each firm's dominant strategy and the Nash equilibrium from a 2×2 payoff matrix, and explain why the cooperative outcome is hard to sustain.

Bahasa Indonesia

Sebuah oligopoli adalah pasar dengan sedikit perusahaan besar yang saling bergantung satu sama lain (mobil, maskapai penerbangan, ponsel). Karena keputusan terbaik setiap perusahaan bergantung pada langkah pesaingnya, kita menganalisisnya menggunakan teori permainan.

Sebuah matriks pembayaran menunjukkan keuntungan setiap perusahaan untuk setiap kombinasi pilihan.
Strategi dominan adalah pilihan terbaik perusahaan tanpa memandang apa yang dilakukan oleh pesaingnya.
Keseimbangan Nash adalah hasil di mana tidak ada perusahaan yang dapat melakukan lebih baik dengan mengubah pilihannya secara sepihak.
Dilema tahanan klasik menunjukkan mengapa perusahaan sering gagal berkolusi: keduanya akan untung dengan berkolusi (bertindak seperti monopoli), tetapi masing-masing memiliki insentif untuk curang, sehingga mereka berakhir pada hasil yang mirip persaingan dengan keuntungan lebih rendah. Kolusi dan kartel tidak stabil karena alasan yang sama (dan biasanya ilegal).

Contoh terpecahkan. Dua perusahaan masing-masing memilih harga Tinggi atau Rendah. Keuntungan (A, B): keduanya Tinggi $\to(10,10)$; A Rendah, B Tinggi $\to(14,4)$; A Tinggi, B Rendah $\to(4,14)$; keduanya Rendah $\to(6,6)$. Untuk A: jika B bermain Tinggi, Rendah ($14$) mengalahkan Tinggi ($10$); jika B bermain Rendah, Rendah ($6$) mengalahkan Tinggi ($4$) – jadi Rendah adalah strategi dominan A, dan secara simetris juga milik B. Keseimbangan Nash adalah keduanya Rendah $(6,6)$, yang lebih buruk bagi kedua belah pihak daripada hasil kooperatif $(10,10)$ – dilema tahanan dalam aksi.

Dilema tahanan: strategi dominan setiap perusahaan adalah Rendah, menghasilkan keseimbangan Nash

Keterampilan ujian: mampu menemukan strategi dominan setiap perusahaan dan keseimbangan Nash dari matriks pembayaran 2×2, serta menjelaskan mengapa hasil kooperatif sulit dipertahankan.

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
payoff matrix/ˈpeɪɒf ˈmeɪtrɪks/	matriks payoff
dominant strategy/ˈdɒmɪnənt ˈstrætədʒi/	strategi dominan
Nash equilibrium/næʃ ˌiːkwɪˈlɪbrɪəm/	Ekuilibrium Nash
prisoners' dilemma/ˈprɪzənəz daɪˈlemə/	Dilema tahanan
colluding/kəˈluːdɪŋ/	Kolusi
cartels/kɑːˈtelz/	Kartel

4.5

Exam tips · ⁨Tips ujian⁩

English

A firm with market power faces a downward-sloping demand, so MR < P (MR has twice the slope).
A monopoly produces where MR = MC, then charges the price up on the demand curve; it makes deadweight loss because $P > MC$.
Under perfect price discrimination the firm produces the efficient quantity but captures all consumer surplus.
Monopolistic competition earns zero long-run profit with excess capacity (product variety is the trade-off).
In an oligopoly find the dominant strategy and Nash equilibrium from the payoff matrix; the cooperative outcome is hard to sustain.

Bahasa Indonesia

Perusahaan dengan kekuatan pasar menghadapi kurva permintaan menurun, sehingga MR < P (MR memiliki kemiringan dua kali lipatnya).
Monopoli memproduksi di mana MR = MC, kemudian menetapkan harga naik pada kurva permintaan; ia menciptakan hilangnya surplus masyarakat karena $P > MC$.
Di bawah pembedaan harga sempurna, perusahaan memproduksi jumlah efisien tetapi menguasai seluruh surplus konsumen.
Persaingan monopolistik menghasilkan nol laba jangka panjang dengan kapasitas berlebih (variasi produk adalah komprominya).
Dalam oligopoli, temukan strategi dominan dan keseimbangan Nash dari matriks pembayaran; hasil kooperatif sulit dipertahankan.

Factor Markets · ⁨Pasar Faktor Produksi⁩

Watch lesson · ⁨Tonton pelajaran⁩

Open this topic on its own page · ⁨Buka topik ini di halaman sendiri⁩

5.1

Introduction to Factor Markets · ⁨Pengantar Pasar Faktor⁩

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-4): Factor prices provide incentives and convey information to firms and factors of production.

Learning Objective PRD-4.A: a. Define (using graphs where appropriate) key terms and concepts relating to factor markets. b. Explain (using graphs where appropriate) the relationship between factors of production, firms, and factor prices. c. Calculate (using data from a graph or table where appropriate) the marginal revenue product and marginal resource cost.

PRD-4.A.1 Factors of production (labor, capital, and land) respond to factor prices (wages, interest, and rent), and employers' (firms') decision to hire is based on the productivity of the factors, output price, and cost of the factor.
PRD-4.A.2 The quantity of labor demanded is negatively related to the wage rate, while the quantity of labor supplied is positively related to the wage rate in a given labor market, other things constant.

Bahasa Indonesia

Pemahaman Berkelanjutan (PRD-4): Harga faktor memberikan insentif dan menyampaikan informasi kepada perusahaan dan faktor produksi.

Tujuan Pembelajaran PRD-4.A: a. Definisikan (menggunakan grafik jika sesuai) istilah dan konsep kunci yang berkaitan dengan pasar faktor. b. Jelaskan (menggunakan grafik jika sesuai) hubungan antara faktor produksi, perusahaan, dan harga faktor. c. Hitung (menggunakan data dari grafik atau tabel jika sesuai) produk pendapatan marjinal dan biaya sumber daya marjinal.

PRD-4.A.1 Faktor produksi (tenaga kerja, modal, dan tanah) merespons harga faktor (upah, bunga, dan sewa), dan keputusan pemberi kerja (perusahaan) untuk merekrut didasarkan pada produktivitas faktor, harga output, dan biaya faktor.
PRD-4.A.2 Kuantitas tenaga kerja yang diminta berbanding terbalik dengan tingkat upah, sementara kuantitas tenaga kerja yang ditawarkan berbanding lurus dengan tingkat upah dalam suatu pasar tenaga kerja tertentu, dengan asumsi lain tetap.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

English

A factor market 要素市场 is where firms buy the factors of production – labor, land, capital. The roles reverse: firms demand and households supply. The most-tested factor is labor.

Factor demand is a derived demand 派生需求 – firms want labor not for itself but for the output (and revenue) it produces. So the demand for workers depends on the demand for the product they make.

Bahasa Indonesia

Pabrik pakaian: pasar faktor menentukan upah untuk tenaga kerja dan input lainnya

Sebuah pasar faktor adalah tempat perusahaan membeli faktor produksi – tenaga kerja, tanah, modal. Peran berbalik: perusahaan meminta dan rumah tangga menyediakan. Faktor yang paling sering diuji adalah tenaga kerja.

Pasar tenaga kerja kompetitif menetapkan upah di mana permintaan tenaga kerja bertemu penawaran tenaga kerja

Permintaan faktor adalah permintaan turunan – perusahaan menginginkan tenaga kerja bukan untuk dirinya sendiri melainkan untuk output (dan pendapatan) yang dihasilkannya. Jadi, permintaan terhadap pekerja bergantung pada permintaan terhadap produk yang mereka buat.

Explore · ⁨Jelajahi⁩

A labour (factor) market · ⁨Pasar tenaga kerja (faktor)⁩

In a factor market firms demand labour and households supply it; the wage settles where demand meets supply. Shift either curve and watch the wage and employment move. · ⁨Dalam pasar faktor, perusahaan meminta tenaga kerja dan rumah tangga menawarkannya; upah ditetapkan di titik pertemuan permintaan dan penawaran. Geser salah satu kurva dan amati pergerakan upah dan tingkat pekerjaan.⁩

5.2

Changes in Factor Demand and Factor Supply · ⁨Perubahan Permintaan dan Penawaran Faktor⁩

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-4): Factor prices provide incentives and convey information to firms and factors of production.

Learning Objective PRD-4.B: Explain (using graphs where appropriate) firms' and factors' responses to changes in incentives and constraints.

PRD-4.B.1 Changes in the determinants of labor demand, such as the output price and the productivity of the worker, cause the labor demand curve to shift.
PRD-4.B.2 Changes in the determinants of labor supply (such as immigration, education, working conditions, age distribution, availability of alternative options, preferences for leisure, and cultural expectations) cause the labor supply curve to shift.

Bahasa Indonesia

Pemahaman Berkelanjutan (PRD-4): Harga faktor memberikan insentif dan menyampaikan informasi kepada perusahaan dan faktor produksi.

Tujuan Pembelajaran PRD-4.B: Jelaskan (menggunakan grafik jika sesuai) respons perusahaan dan faktor terhadap perubahan insentif dan kendala.

PRD-4.B.1 Perubahan dalam penentu permintaan tenaga kerja, seperti harga output dan produktivitas pekerja, menyebabkan kurva permintaan tenaga kerja bergeser.
PRD-4.B.2 Perubahan dalam penentu penawaran tenaga kerja (seperti imigrasi, pendidikan, kondisi kerja, distribusi usia, ketersediaan opsi alternatif, preferensi untuk waktu santai, dan ekspektasi budaya) menyebabkan kurva penawaran tenaga kerja bergeser.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

English

Labor demand shifts when:

the product price or product demand changes (more valuable output $\Rightarrow$ more labor demanded),
worker productivity changes (better training or capital),
the price of other inputs changes (a substitute input like machines, or a complement).

Labor supply shifts with the number of qualified workers, immigration, workers' preferences (wages needed to attract them), and the wages available in other jobs. The market wage is set where labor demand meets labor supply.

Bahasa Indonesia

Permintaan tenaga kerja bergeser ketika:

harga produk atau permintaan produk berubah (output lebih berharga $\Rightarrow$ lebih banyak tenaga kerja diminta),
produktivitas pekerja berubah (pelatihan lebih baik atau modal),
harga input lain berubah (input pengganti seperti mesin, atau pelengkap).

Penawaran tenaga kerja bergeser dengan jumlah pekerja berkualifikasi, imigrasi, preferensi pekerja (upah yang diperlukan untuk menarik mereka), dan upah yang tersedia di pekerjaan lain. Upah pasar ditetapkan di mana permintaan tenaga kerja bertemu penawaran tenaga kerja.

5.3

Profit-Maximizing Behavior in Perfectly Competitive Factor Markets · ⁨Perilaku Memaksimalkan Laba di Pasar Faktor Kompetitif Sempurna⁩

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-4): Factor prices provide incentives and convey information to firms and factors of production.

Learning Objective PRD-4.C: a. Define (using graphs as appropriate) the characteristics of perfectly competitive factor markets. b. Explain (using graphs where appropriate) the profit-maximizing behavior of firms buying labor (with other inputs fixed) in perfectly competitive markets. c. Calculate (using data from a graph or table where appropriate) measures representing the profit-maximizing behavior of firms buying labor (with other inputs fixed) in perfectly competitive markets.

PRD-4.C.1 In a perfectly competitive labor market, the wage is set by the market and each firm hires the quantity of workers, where the marginal factor (resource) cost (wage) equals the marginal revenue product of labor. A typical firm may be a perfect competitor in the labor market even if it is an imperfect competitor in its output markets.
PRD-4.C.2 A typical firm hires labor in a perfectly competitive labor market as long as the marginal revenue product of labor is greater than the market wage.
PRD-4.C.3 To minimize costs or maximize profits, firms allocate inputs such that the last dollar spent on each input yields the same amount of marginal product.

Bahasa Indonesia

Pemahaman Berkelanjutan (PRD-4): Harga faktor memberikan insentif dan menyampaikan informasi kepada perusahaan dan faktor produksi.

Tujuan Pembelajaran PRD-4.C: a. Definisikan (menggunakan grafik jika sesuai) karakteristik pasar faktor kompetitif sempurna. b. Jelaskan (menggunakan grafik jika sesuai) perilaku maximization laba perusahaan yang membeli tenaga kerja (dengan input lain tetap) di pasar kompetitif sempurna. c. Hitung (menggunakan data dari grafik atau tabel jika sesuai) ukuran yang mewakili perilaku maximization laba perusahaan yang membeli tenaga kerja (dengan input lain tetap) di pasar kompetitif sempurna.

PRD-4.C.1 Di pasar tenaga kerja kompetitif sempurna, upah ditentukan oleh pasar dan setiap perusahaan merekrut jumlah pekerja di mana biaya faktor (sumber daya) marjinal (upah) sama dengan produk pendapatan marjinal tenaga kerja. Perusahaan biasa mungkin merupakan pesaing sempurna di pasar tenaga kerja meskipun ia adalah pesaing tidak sempurna di pasar outputnya.
PRD-4.C.2 Perusahaan biasa merekrut tenaga kerja di pasar tenaga kerja kompetitif sempurna selama produk pendapatan marjinal tenaga kerja lebih besar daripada upah pasar.
PRD-4.C.3 Untuk meminimalkan biaya atau memaksimalkan laba, perusahaan mengalokasikan input sedemikian rupa sehingga dollar terakhir yang dihabiskan untuk setiap input menghasilkan jumlah produk marjinal yang sama.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

English

A firm decides how many workers to hire with the same marginal logic as everything else – compare the marginal benefit and marginal cost of one more worker.

The marginal benefit of a worker is the marginal revenue product 边际收益产品 (MRP): the extra revenue from one more worker, $MRP = MP \times$ product price (in a competitive product market, where $P=MR$). MRP falls as more workers are hired, because of diminishing marginal product.
The marginal cost of a worker is the wage (in a competitive labor market the firm is a wage taker, so marginal factor cost $=$ the wage).
Hiring rule: hire workers up to where $MRP = \text{wage}$ (more generally, $MRP = MFC$). The MRP curve is the firm's labor demand curve.

Worked example. A worker's marginal product is $8$ units and the firm sells each in a competitive market for $\$5$, so $MRP=8\times\$5=\$40$. If the wage is $\$30$, the firm hires this worker because $MRP>\text{wage}$. As more workers join, diminishing marginal product pulls MRP down; the firm keeps hiring until a worker whose $MP=6$ gives $MRP=6\times\$5=\$30$, exactly the wage – the profit-maximizing stopping point.

To choose the least-cost combination of two inputs, set the MP-per-dollar equal across inputs: $\dfrac{MP_L}{P_L}=\dfrac{MP_K}{P_K}$ – the same equal-bang-per-buck rule as consumer choice.

Exam skill: compute MRP from a table (marginal product $\times$ price) and find how many workers to hire at a given wage – a common free-response task.

Bahasa Indonesia

Perusahaan memutuskan berapa banyak pekerja yang akan disewa dengan logika margin yang sama seperti segalanya – membandingkan manfaat marjinal dan biaya marjinal dari satu pekerja tambahan.

Manfaat marjinal seorang pekerja adalah produk pendapatan marjinal (MRP): pendapatan ekstra dari satu pekerja tambahan, $MRP = MP \times$ harga produk (di pasar produk kompetitif, di mana $P=MR$). MRP turun semakin banyak pekerja disewa, karena produk marjinal yang menurun.
Biaya marjinal seorang pekerja adalah upah (di pasar tenaga kerja kompetitif, perusahaan adalah penerima upah, sehingga biaya faktor marjinal $=$ upah).
Aturan menyewa: sewa pekerja hingga titik di mana $MRP = \text{wage}$ (secara umum, $MRP = MFC$). Kurva MRP adalah kurva permintaan tenaga kerja perusahaan.

Contoh kerja. Marginal produk seorang pekerja adalah $8$ unit dan perusahaan menjual setiap unit tersebut dalam pasar kompetitif seharga $\$5$, so $MRP=8\times\$5=\$40$. If the wage is $\$30$, perusahaan mempekerjakan pekerja ini karena $MRP>\text{wage}$. Semakin banyak pekerja yang bergabung, marginal produk yang semakin menurun menarik MRP ke bawah; perusahaan terus mempekerjakan hingga seorang pekerja whose $MP=6$ memberikan $MRP=6\times\$5=\$30$, tepat sebesar upah—titik berhenti yang memaksimumkan laba.

Untuk memilih kombinasi biaya terendah dari dua input, tetapkan MP per dolar setara di seluruh input: $\dfrac{MP_L}{P_L}=\dfrac{MP_K}{P_K}$ – aturan bang-per-buck yang sama seperti pemilihan konsumen.

Keterampilan ujian: hitung MRP dari tabel (produk marjinal $\times$ harga) dan temukan berapa banyak pekerja yang harus disewa pada upah tertentu – tugas respons bebas yang umum.

Jalur perakitan mobil: perusahaan menyewa tenaga kerja hingga produk pendapatan marjinal sama dengan upah

5.4

Monopsonistic Markets · ⁨Pasar Monopsonistik⁩

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (PRD-4): Factor prices provide incentives and convey information to firms and factors of production.

Learning Objective PRD-4.D: a. Define (using graphs as appropriate) the characteristics of monopsonistic markets. b. Explain (using graphs where appropriate) the profit-maximizing behavior of firms buying labor (with other inputs fixed) in monopsonistic markets. c. Calculate (using data from a graph or table where appropriate) measures representing the profit-maximizing behavior of firms buying labor (with other inputs fixed) in monopsonistic markets.

PRD-4.D.1 In a monopsonistic labor market, a typical firm hires additional labor as long as the marginal revenue product is greater than the marginal factor (resource) cost (the wage of a new unit of labor plus the wage increase given to all existing labor).
PRD-4.D.2 When a typical firm hires additional workers in a monopsonistic labor market, the marginal factor (resource) cost is greater than the supply price of labor.

Bahasa Indonesia

Pemahaman Berkelanjutan (PRD-4): Harga faktor memberikan insentif dan menyampaikan informasi kepada perusahaan dan faktor produksi.

Tujuan Pembelajaran PRD-4.D: a. Definisikan (menggunakan grafik jika sesuai) karakteristik pasar monopsonistik. b. Jelaskan (menggunakan grafik jika sesuai) perilaku maximization laba perusahaan yang membeli tenaga kerja (dengan input lain tetap) di pasar monopsonistik. c. Hitung (menggunakan data dari grafik atau tabel jika sesuai) ukuran yang mewakili perilaku maximization laba perusahaan yang membeli tenaga kerja (dengan input lain tetap) di pasar monopsonistik.

PRD-4.D.1 Di pasar tenaga kerja monopsonistik, perusahaan biasa merekrut tenaga kerja tambahan selama produk pendapatan marjinal lebih besar daripada biaya faktor (sumber daya) marjinal (upah unit tenaga kerja baru ditambah kenaikan upah yang diberikan kepada semua tenaga kerja yang sudah ada).
PRD-4.D.2 Ketika perusahaan biasa merekrut pekerja tambahan di pasar tenaga kerja monopsonistik, biaya faktor (sumber daya) marjinal lebih besar daripada harga penawaran tenaga kerja.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

English

A monopsony 买方垄断 is a market with a single buyer of a factor – for example, the only large employer in a town.

Because it is the whole market, the monopsonist faces an upward-sloping labor supply curve: to hire more workers it must raise the wage for everyone.
So the marginal factor cost 边际要素成本 (MFC) is above the wage (like $MR for a monopoly, in reverse), and the MFC curve lies above the supply curve.
The monopsonist hires where $MRP = MFC$, then pays the lower wage the supply curve allows at that quantity.
Result: compared with a competitive labor market, a monopsony hires fewer workers at a lower wage – the mirror image of monopoly.

Exam skill: draw the monopsony graph (supply, MFC above it, MRP as demand), mark quantity at $MRP=MFC$ and the wage down on the supply curve, and contrast it with the competitive wage and quantity.

Bahasa Indonesia

Sebuah monopsony adalah pasar dengan satu pembeli faktor – misalnya, satu-satunya pemberi kerja besar di sebuah kota.

Karena merupakan keseluruhan pasar, monopsonis menghadapi kurva penawaran tenaga kerja menanjak: untuk merekrut lebih banyak pekerja, ia harus menaikkan upah untuk semua orang.
Jadi biaya faktor marjinal (MFC) berada di atas upah (seperti $MR untuk monopoli, terbalik), dan kurva MFC terletak di atas kurva penawaran.
Monopsonis merekrut tenaga kerja pada saat $MRP = MFC$, kemudian membayar upah yang lebih rendah yang diizinkan oleh kurva penawaran pada jumlah tersebut.
Hasil: dibandingkan dengan pasar tenaga kerja kompetitif, monopsoni merekrut lebih sedikit pekerja dengan upah yang lebih rendah – cerminan dari monopoli.

Monopsonis merekrut tenaga kerja di mana MFC = MRP dan membayar upah lebih rendah daripada pasar kompetitif

Keterampilan ujian: gambar grafik monopsoni (penawaran, MFC di atasnya, MRP sebagai permintaan), tandai kuantitas pada $MRP=MFC$ dan turunkan upah ke kurva penawaran, lalu bandingkan dengan upah dan kuantitas kompetitif.

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
factor market/ˈfæktə ˈmɑːkɪt/	pasar faktor
derived demand/dɪˈraɪvd dɪˈmænd/	permintaan turunan
marginal revenue product/ˈmɑːdʒɪnl ˈrevənjuː ˈprɒdʌkt/	produk pendapatan marginal
monopsony/ˈmɒnəʊpsəni/	monopsony
marginal factor cost/ˈmɑːdʒɪnl ˈfæktə kɒst/	biaya faktor marginal

5.4

Exam tips · ⁨Tips ujian⁩

English

Factor demand is derived demand; hire labour up to where MRP = wage (MRP = marginal product × price).
MRP falls as more workers are hired (diminishing marginal product).
For least-cost input use, equalise the marginal product per dollar across inputs.
A monopsony faces an upward supply, so its marginal factor cost is above the wage; it hires fewer workers at a lower wage.
Draw the monopsony graph (supply, MFC above it, MRP as demand) and contrast with the competitive outcome.

Bahasa Indonesia

Permintaan faktor adalah permintaan turunan; rekrutlah tenaga kerja hingga titik di mana MRP = upah (MRP = produk marjinal × harga).
MRP menurun ketika semakin banyak pekerja direkrut (produk marjinal yang menurun).
Untuk penggunaan input biaya terendah, samakan produk marjinal per dolar di seluruh input.
Monopsoni menghadapi penawaran yang menanjak, sehingga biaya faktor marjinalnya di atas upah; ia merekrut lebih sedikit pekerja dengan upah yang lebih rendah.
Gambar grafik monopsoni (penawaran, MFC di atasnya, MRP sebagai permintaan) dan bandingkan dengan hasil kompetitif.

Market Failure and the Role of Government · ⁨Kegagalan Pasar dan Peran Pemerintah⁩

Watch lesson · ⁨Tonton pelajaran⁩

Open this topic on its own page · ⁨Buka topik ini di halaman sendiri⁩

6.1

Socially Efficient and Inefficient Market Outcomes

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (POL-2): Perfectly competitive markets allocate resources efficiently, but imperfect competition often results in market inefficiencies.

Learning Objective POL-2.A: a. Define social efficiency. b. Explain (using graphs where appropriate) why resource allocation in perfectly competitive markets is socially efficient.

POL-2.A.1 The optimal quantity of a good occurs where the marginal benefit of consuming the last unit equals the marginal cost of producing that last unit, thus maximizing total economic surplus.
POL-2.A.2 The market equilibrium quantity is equal to the socially optimal quantity only when all social benefits and costs are internalized by individuals in the market. Total economic surplus is maximized at that quantity. [See also PRD-3 and POL-3.]

Learning Objective POL-2.B: Explain (using graphs where appropriate) how private incentives can lead to actions by rational agents that are socially undesirable (inefficient) market outcomes.

POL-2.B.1 Rational agents can pursue private actions to exploit or exercise market characteristics known as market power.
POL-2.B.2 Rational agents make optimal decisions by equating private marginal benefits and private marginal costs that can result in market inefficiencies.
POL-2.B.3 Policymakers use cost-benefit analysis to evaluate different actions to reduce or eliminate market inefficiencies.
POL-2.B.4 Market inefficiencies can be eliminated by designing policies that equate marginal social benefit with marginal social cost.

Learning Objective POL-2.C: a. Explain equilibrium allocations in imperfect markets relative to efficient allocations (using graphs where appropriate) and why these markets are inefficient. b. Calculate (using graphs where appropriate) the deadweight loss resulting from the production of a non-efficient quantity.

POL-2.C.1 Equilibrium allocations can deviate from efficient allocations due to situations such as monopoly; oligopoly; monopolistic competition; negative and positive externalities in production or consumption; asymmetric information; and insufficient production of public goods.
POL-2.C.2 Producing any non-efficient quantity results in deadweight loss.

Bahasa Indonesia

Pemahaman Berkelanjutan (POL-2): Pasar kompetitif sempurna mengalokasikan sumber daya secara efisien, tetapi persaingan tidak sempurna sering kali mengakibatkan inefisiensi pasar.

Tujuan Pembelajaran POL-2.A: a. Definisikan efisiensi sosial. b. Jelaskan (menggunakan grafik jika sesuai) mengapa alokasi sumber daya di pasar kompetitif sempurna bersifat efisien secara sosial.

POL-2.A.1 Kuantitas optimal suatu barang terjadi di mana manfaat marjinal dari konsumsi unit terakhir sama dengan biaya marjinal dari produksi unit terakhir tersebut, sehingga memaksimalkan surplus ekonomi total.
POL-2.A.2 Kuantitas keseimbangan pasar sama dengan kuantitas optimal secara sosial hanya ketika seluruh manfaat dan biaya sosial diinternalisasi oleh individu di pasar. Surplus ekonomi total dimaksimalkan pada kuantitas tersebut. [Lihat juga PRD-3 dan POL-3].

Tujuan Pembelajaran POL-2.B: Jelaskan (menggunakan grafik jika sesuai) bagaimana insentif pribadi dapat mengarah pada tindakan oleh agen rasional yang menghasilkan hasil pasar yang tidak diinginkan secara sosial (inefisien).

POL-2.B.1 Agen rasional dapat mengambil tindakan pribadi untuk mengeksploitasi atau menggunakan karakteristik pasar yang dikenal sebagai kekuatan pasar.
POL-2.B.2 Agen rasional membuat keputusan optimal dengan menyamakan manfaat marjinal pribadi dan biaya marjinal pribadi, yang dapat menyebabkan inefisiensi pasar.
POL-2.B.3 Pembuat kebijakan menggunakan analisis biaya-manfaat untuk mengevaluasi berbagai tindakan guna mengurangi atau menghilangkan inefisiensi pasar.
POL-2.B.4 Inefisiensi pasar dapat dihilangkan melalui perancangan kebijakan yang menyamakan manfaat sosial marjinal dengan biaya sosial marjinal.

Tujuan Pembelajaran POL-2.C: a. Jelaskan alokasi keseimbangan dalam pasar tidak sempurna relatif terhadap alokasi efisien (menggunakan grafik jika sesuai) dan mengapa pasar-pasar tersebut tidak efisien. b. Hitung (menggunakan grafik jika sesuai) hilangnya surplus mati yang timbul dari produksi kuantitas yang tidak efisien.

POL-2.C.1 Alokasi keseimbangan dapat menyimpang dari alokasi efisien akibat situasi seperti monopoli; oligopoli; persaingan monopolistik; eksternalitas negatif dan positif dalam produksi atau konsumsi; informasi asimetris; dan produksi barang publik yang tidak memadai.
POL-2.C.2 Memproduksi kuantitas apa pun yang tidak efisien akan menghasilkan hilangnya surplus mati.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

A market outcome is socially efficient 社会有效率 when it maximizes total surplus – when the marginal social benefit equals the marginal social cost of the last unit. Perfect competition reaches this on its own. But sometimes markets fail to, producing too much or too little. This is market failure 市场失灵, and it is the main economic justification for government action.

Productive efficiency is lowest cost; allocative efficiency is making what people want

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
socially efficient/ˈsəʊʃəli ɪˈfɪʃənt/	efisien secara sosial
market failure/ˈmɑːkɪt ˈfeɪlɪə/	kegagalan pasar

6.2

Externalities

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (POL-3): Private incentives can fail to account for all socially relevant considerations.

Learning Objective POL-3.A: a. Define externalities. b. Explain (using graphs where appropriate) how in the presence of externalities, private markets do not take into consideration social costs or social benefits.

POL-3.A.1 The socially optimal quantity of a good occurs where the marginal social benefit of consuming the last unit equals the marginal social cost of producing that last unit, thus maximizing total economic surplus.
POL-3.A.2 Externalities are either positive or negative and arise from lack of well-defined property rights and/or high transaction costs.
POL-3.A.3 In the presence of externalities, rational agents respond to private costs and benefits and not to external costs and benefits.
POL-3.A.4 Rational agents have the incentive to free ride when a good is non-excludable.

Learning Objective POL-3.B: Explain (using graphs where appropriate) how public policies address positive or negative externalities.

POL-3.B.1 Policies that address positive or negative externalities include taxes/subsidies, environmental regulation, public provision, the assignment of property rights, and the reassignment of property rights through private transactions.

Bahasa Indonesia

Pemahaman Berkelanjutan (POL-3): Insentif pribadi dapat gagal memperhitungkan semua pertimbangan yang relevan secara sosial.

Tujuan Pembelajaran POL-3.A: a. Definisikan eksternalitas. b. Jelaskan (menggunakan grafik jika sesuai) bagaimana dalam kehadiran eksternalitas, pasar pribadi tidak memperhitungkan biaya sosial atau manfaat sosial.

POL-3.A.1 Kuantitas sosial optimum dari suatu barang terjadi ketika manfaat sosial marjinal dari konsumsi unit terakhir sama dengan biaya sosial marjinal dari produksi unit terakhir tersebut, sehingga memaksimalkan total surplus ekonomi.
POL-3.A.2 Eksternalitas bersifat positif atau negatif dan muncul akibat ketiadaan hak milik yang terdefinisi dengan baik dan/atau biaya transaksi yang tinggi.
POL-3.A.3 Dalam kehadiran eksternalitas, agen rasional merespons biaya dan manfaat pribadi, bukan biaya dan manfaat eksternal.
POL-3.A.4 Agen rasional memiliki insentif untuk bebas berkuda ketika suatu barang tidak dapat dieksklusi.

Tujuan Pembelajaran POL-3.B: Jelaskan (menggunakan grafik jika sesuai) bagaimana kebijakan publik mengatasi eksternalitas positif atau negatif.

POL-3.B.1 Kebijakan yang mengatasi eksternalitas positif atau negatif meliputi pajak/subsidi, regulasi lingkungan, penyediaan publik, penetapan hak milik, dan penugasan kembali hak milik melalui transaksi swasta.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Cigarettes: externalities mean private markets may not reach socially efficient outcomes

Negative externalities

An externality 外部性 is a cost or benefit that falls on a third party not involved in the transaction – so the private decision-makers ignore it.

A negative externality: the market over-produces, causing a welfare loss

A negative externality 负外部性 (pollution) means marginal social cost > marginal private cost. The market over-produces; the deadweight loss is a triangle. Fixes: a Pigovian tax 庇古税 or regulation to make producers "internalize" the cost (shifting private cost up to social cost).
A positive externality 正外部性 (vaccination, education) means marginal social benefit > marginal private benefit. The market under-produces. Fixes: a subsidy to consumers or producers.
Coase theorem 科斯定理: if property rights are clear and bargaining is costless, private parties can solve an externality themselves – but that is rare with many people involved.

A city street jammed nose-to-tail with cars at a standstill — Congestion is a negative externality: each driver imposes a cost on every other driver that no price collects

Worked example. A factory's private marginal cost of a chemical is $\$8$ per unit, but each unit also dumps $\$3$ of pollution on neighbors, so the marginal social cost is $\$11$. Ignoring the $\$3$, the market over-produces. A Pigovian tax of exactly $\$3$ per unit raises the firm's private cost to $\$11$ – now equal to the social cost – so the firm cuts output to the efficient quantity and the externality is "internalized."

Exam skill: identify whether an externality is positive or negative, show on a graph that private and social curves diverge, mark the deadweight loss, and name the correcting tax or subsidy.

Industrial pollution: a negative externality where social cost exceeds private cost

Explore · ⁨Jelajahi⁩

A market with an externality · ⁨Pasar dengan eksternalitas⁩

An externality makes private cost differ from social cost, so the free-market quantity is inefficient. See the deadweight loss and how a tax or subsidy corrects it. · ⁨Eksternalitas membuat biaya pribadi berbeda dari biaya sosial, sehingga kuantitas pasar bebas menjadi tidak efisien. Lihat hilangnya beban mati dan bagaimana pajak atau subsidi memperbaikinya.⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
externality/ekˈstɜːnælɪti/	eksternalitas
negative externality/ˈneɡətɪv ekˈstɜːnælɪti/	eksternalitas negatif
Pigovian tax/pɪˈɡəʊvɪən tæks/	Pajak Pigovian
positive externality/ˈpɒzɪtɪv ekˈstɜːnælɪti/	eksternalitas positif
Coase theorem/kəʊs ˈθɪərəm/	Teorema Coase

6.3

Public and Private Goods

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (POL-3): Private incentives can fail to account for all socially relevant considerations.

Learning Objective POL-3.C: a. Define whether goods are rival and/or excludable. b. Explain how the nature of rival and/or excludable goods influences the behavior of individuals and groups.

POL-3.C.1 Private goods are rival and excludable, and public goods are non-rival and non-excludable.
POL-3.C.2 Due to the free rider problem, private individuals usually lack the incentive to produce public goods, leaving government as the only producer.
POL-3.C.3 Governments sometimes choose to produce private goods, such as educational services, and to allow free access to them.
POL-3.C.4 Some natural resources are, by their nature, non-excludable and rival and therefore open access. Private individuals inefficiently overconsume such resources.

Bahasa Indonesia

Pemahaman Berkelanjutan (POL-3): Insentif pribadi dapat gagal memperhitungkan semua pertimbangan yang relevan secara sosial.

Tujuan Pembelajaran POL-3.C: a. Definisikan apakah barang bersifat rival dan/atau dapat dieksklusi. b. Jelaskan bagaimana sifat barang rival dan/atau dapat dieksklusi mempengaruhi perilaku individu dan kelompok.

POL-3.C.1 Barang pribadi bersifat rival dan dapat dieksklusi, sedangkan barang publik bersifat non-rival dan non-dapat dieksklusi.
POL-3.C.2 Akibat masalah bebas berkuda, individu swasta biasanya kurang memiliki insentif untuk memproduksi barang publik, menjadikan pemerintah sebagai satu-satunya produsen.
POL-3.C.3 Pemerintah terkadang memilih untuk memproduksi barang pribadi, seperti layanan pendidikan, dan mengizinkan akses gratis kepadanya.
POL-3.C.4 Beberapa sumber daya alam, pada dasarnya, bersifat non-dapat dieksklusi dan rival sehingga merupakan akses terbuka. Individu swasta mengonsumsi berlebihan sumber daya semacam itu secara tidak efisien.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Goods differ along two traits: rivalry 竞争性 (does one person's use reduce another's?) and excludability 排他性 (can non-payers be kept out?).

Goods classified by whether they are rival and excludable

A private good 私人物品 is rival and excludable (a sandwich) – markets handle these well.
A public good 公共物品 is non-rival and non-excludable (national defense, a lighthouse). Because non-payers cannot be excluded, people free-ride 搭便车 – enjoy it without paying – so markets under-provide it, and government usually supplies it.
Common resources 公共资源 are rival but non-excludable (ocean fish); over-use ruins them – the tragedy of the commons 公地悲剧.

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
rivalry/ˈraɪvəlri/	persaingan
excludability/eksˌkluːdəˈbɪlɪti/	eksklusivitas
private good/ˈpraɪvət ɡʊd/	barang pribadi
public good/ˈpʌblɪk ɡʊd/	barang publik
free-ride/friː raɪd/	Free-ride (pemanfaatan gratis)
Common resources/ˈkɒmən rɪˈzɔːsɪz/	Sumber daya umum
tragedy of the commons/ˈtrædʒədi ɒvðə ˈkɒmənz/	tragedi sumber daya bersama

6.4

The Effects of Government Intervention in Different Market Structures

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (POL-4): In imperfect markets, well-designed government policy can reduce waste.

Learning Objective POL-4.A: a. Define government policy interventions in imperfect markets. b. Explain (using graphs where appropriate) how government policies can alter market outcomes in perfectly and imperfectly competitive markets. c. Calculate (using data from a graph or table as appropriate) changes in market outcomes resulting from government policies in perfectly competitive and imperfectly competitive markets.

POL-4.A.1 Per-unit taxes and subsidies affect the total price consumers pay, net price firms receive, equilibrium quantity, consumer and producer surpluses, deadweight loss, and government revenue or cost. The impact of change depends on the price elasticity of demand and supply.
POL-4.A.2 Lump-sum taxes and lump-sum subsidies do not change either marginal cost or marginal benefit; only fixed costs will be affected.
POL-4.A.3 Binding price ceilings and floors affect prices and quantities differently depending on the market structures (perfect competition, monopoly, monopolistic competition, and monopsony) and the price elasticities of supply and demand.
POL-4.A.4 Government intervention in imperfect markets can increase efficiency if the policy correctly addresses the incentives that led to the market failure.
POL-4.A.5 Government can use price regulation to address inefficiency due to monopoly.
POL-4.A.6 A natural monopoly will require a lump-sum subsidy to produce at the allocatively efficient quantity.
POL-4.A.7 Governments use antitrust policy in an attempt to make markets more competitive.
- Exclusion statement: A graph of inefficiency and policy due to collusion is beyond the scope of the course and the AP Exam.

Bahasa Indonesia

Pemahaman Berkelanjutan (POL-4): Dalam pasar tidak sempurna, kebijakan pemerintah yang dirancang dengan baik dapat mengurangi pemborosan.

Tujuan Pembelajaran POL-4.A: a. Definisikan intervensi kebijakan pemerintah dalam pasar tidak sempurna. b. Jelaskan (menggunakan grafik jika sesuai) bagaimana kebijakan pemerintah dapat mengubah hasil pasar dalam pasar kompetitif sempurna dan tidak sempurna. c. Hitung (menggunakan data dari grafik atau tabel jika sesuai) perubahan hasil pasar yang dihasilkan oleh kebijakan pemerintah dalam pasar kompetitif sempurna dan tidak sempurna.

POL-4.A.1 Pajak per-unit dan subsidi mempengaruhi total harga yang dibayar konsumen, harga bersih yang diterima perusahaan, kuantitas keseimbangan, surplus konsumen dan produsen, hilangnya surplus mati, serta pendapatan atau biaya pemerintah. Dampak perubahan bergantung pada elastisitas harga permintaan dan penawaran.
POL-4.A.2 Pajak lump-sum dan subsidi lump-sum tidak mengubah biaya marjinal maupun manfaat marjinal; hanya biaya tetap yang akan terpengaruh.
POL-4.A.3 Pengikat batas atas dan bawah harga mempengaruhi harga dan kuantitas secara berbeda tergantung pada struktur pasar (kompetisi sempurna, monopoli, persaingan monopolistik, dan monopsoni) serta elastisitas harga penawaran dan permintaan.
POL-4.A.4 Intervensi pemerintah dalam pasar tidak sempurna dapat meningkatkan efisiensi jika kebijakan tersebut secara tepat menangani insentif yang menyebabkan kegagalan pasar.
POL-4.A.5 Pemerintah dapat menggunakan pengaturan harga untuk mengatasi inefisiensi akibat monopoli.
POL-4.A.6 Monopoli alami memerlukan subsidi lump-sum untuk memproduksi pada kuantitas yang alokatif efisien.
POL-4.A.7 Pemerintah menggunakan kebijakan antitrust untuk berusaha membuat pasar lebih kompetitif.
- Pernyataan eksklusi: Grafik inefisiensi dan kebijakan akibat kolusi berada di luar cakupan kurikulum dan Ujian AP.

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Government tools change outcomes differently by structure:

Regulating a monopoly's price toward $P=MC$ can increase efficiency (unlike a price control in a competitive market, which creates shortage/surplus).
Antitrust laws 反垄断法 break up or block anti-competitive mergers and collusion.
Taxes and subsidies shift output toward the socially efficient quantity when externalities are present.

The key insight: the same policy can help or hurt efficiency depending on whether the market was already efficient (competitive) or already failing (monopoly, externality).

Per-unit vs lump-sum. A per-unit tax 从量税 adds to marginal cost, so it shifts supply up, raises price, cuts quantity, and creates deadweight loss. A lump-sum tax 定额税 (a fixed charge like a licence fee) does not change marginal cost or marginal benefit, so in the short run the profit-maximising price and quantity are unchanged – only the firm's profit falls; in the long run it changes entry and exit. For a natural monopoly, regulating price down to $P=MC$ (allocatively efficient) forces a loss, so a lump-sum subsidy 定额补贴 is needed to keep it producing that efficient quantity.

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
Antitrust laws/ˌæntɪˈtrʌst lɔːz/	Undang-undang antitrust
per-unit tax/pɜː ˈjuːnɪt tæks/	pajak per unit
lump-sum tax/lʌmp sʌm tæks/	Pajak lump-sum
lump-sum subsidy/lʌmp sʌm ˈsʌbsɪdi/	Subsidi lump-sum

6.5

Inequality

Syllabus · ⁨Silabus⁩

English

Enduring Understanding (POL-5): Market outcomes can result in income inequality.

Learning Objective POL-5.A: Define measures of economic inequality in income and wealth.

POL-5.A.1 Income levels and poverty rates vary greatly both across and within groups (e.g., age, gender, race) and countries.
POL-5.A.2 The Lorenz curve and Gini coefficient are used to represent the degree of inequality in distributions and to compare distributions across different countries, policies, or time periods.
- Exclusion statement: Drawing the Lorenz curve and calculating Gini coefficients are beyond the scope of the course and the AP Exam.

Learning Objective POL-5.B: Explain sources of income and wealth inequality.

POL-5.B.1 Each factor of production receives the value of its marginal product, which can contribute to income inequality.
POL-5.B.2 Sources of income and wealth inequality include differences in tax structures (progressive and regressive tax structures), human capital, social capital, inheritance, effects of discrimination, access to financial markets, mobility, and bargaining power within economic and social units (firms, labor unions, and families).

Bahasa Indonesia

Pemahaman Berkelanjutan (POL-5): Hasil pasar dapat mengakibatkan ketidaksetaraan pendapatan.

Tujuan Pembelajaran POL-5.A: Definisikan ukuran ketidaksetaraan ekonomi dalam pendapatan dan kekayaan.

POL-5.A.1 Tingkat pendapatan dan tingkat kemiskinan bervariasi sangat besar baik antar maupun dalam kelompok (misalnya: usia, gender, ras) dan negara-negara.
POL-5.A.2 Kurva Lorenz dan koefisien Gini digunakan untuk merepresentasikan derajat ketidaksetaraan dalam distribusi dan untuk membandingkan distribusi lintas negara, kebijakan, atau periode waktu yang berbeda.
- Pernyataan Pengecualian: Menggambar kurva Lorenz dan menghitung koefisien Gini berada di luar ruang lingkup mata kuliah dan Ujian AP.

Tujuan Pembelajaran POL-5.B: Jelaskan sumber ketimpangan pendapatan dan kekayaan.

POL-5.B.1 Setiap faktor produksi menerima nilai dari produk marjinalnya, yang dapat berkontribusi pada ketimpangan pendapatan.
POL-5.B.2 Sumber ketimpangan pendapatan dan kekayaan meliputi perbedaan dalam struktur pajak (struktur pajak progresif dan regresif), modal manusia, modal sosial, warisan, efek diskriminasi, akses ke pasar keuangan, mobilitas, dan kekuatan tawar dalam unit ekonomi dan sosial (perusahaan, serikat pekerja, dan keluarga).

Source: College Board AP Course and Exam Description · ⁨Sumber: Deskripsi Kursus dan Ujian College Board AP⁩

Markets reward productivity, but the resulting income distribution 收入分配 can be very unequal. Economists measure it with the Lorenz curve 洛伦兹曲线 (share of income against share of population; the further it bows from the 45° line, the more unequal) and the Gini coefficient 基尼系数 (0 = perfect equality, 1 = perfect inequality).

The Lorenz curve and Gini coefficient measure income inequality

Worked example. Suppose the poorest $20\%$ of households earn just $5\%$ of income, while the richest $20\%$ earn $50\%$. Under perfect equality each $20\%$ would earn exactly $20\%$, so the Lorenz curve would be the $45°$ line. Because the bottom fifth is well below $20\%$ and the top fifth well above, the curve bows far beneath the diagonal – a large gap that means a high Gini coefficient and substantial inequality.

Sources of inequality include differences in human capital 人力资本 (skills, education), inheritance, and discrimination. Governments redistribute through progressive taxes 累进税 (higher rates on higher incomes) and transfer payments 转移支付 (welfare, subsidies). There is a debated efficiency–equity trade-off 效率与公平权衡: redistribution can reduce work incentives, so societies balance fairness against the size of the total pie.

Wealth and poverty side by side: markets alone may leave large income inequality unaddressed

Explore · ⁨Jelajahi⁩

Measure inequality with a Lorenz curve · ⁨Ukur ketimpangan dengan kurva Lorenz⁩

A Lorenz curve plots cumulative income against cumulative population; the further it bows from the diagonal, the more unequal — summarised by the Gini coefficient. · ⁨Kurva Lorenz memplot pendapatan kumulatif terhadap populasi kumulatif; semakin jauh melengkung dari garis diagonal, semakin tidak merata — diringkas oleh koefisien Gini.⁩

Vocabulary · ⁨Kosa kata⁩ Train · ⁨Latih⁩

English	Bahasa Indonesia
income distribution/ˈɪŋkʌm ˌdɪstrɪˈbjuːʃn/	distribusi pendapatan
Lorenz curve/ˈlɒrənts kɜːv/	kurva Lorenz
Gini coefficient/ˈdʒiːni ˌkəʊɪˈfɪʃənt/	Koefisien Gini
human capital/ˈhjuːmən ˈkæpɪtl/	modal manusia
progressive taxes/prəˈɡresɪv ˈtæksɪz/	pajak progresif
transfer payments/ˈtrænsfɜː ˈpeɪmənts/	transfer pembayaran
efficiency–equity trade-off/ɪˈfɪʃənsi ˈekwɪti treɪd ɒf/	Trade-off efisiensi–keadilan

6.5

Exam tips

A negative externality makes the market over-produce; correct with a Pigovian tax equal to the external cost. A positive externality under-produces; correct with a subsidy.
A public good is non-rival and non-excludable, so free-riding leads markets to under-provide it.
Classify goods by rivalry and excludability; common resources (rival, non-excludable) suffer the tragedy of the commons.
The same policy can help or hurt efficiency depending on whether the market was already efficient or failing.
Measure inequality with the Lorenz curve and Gini coefficient (0 = equality, 1 = inequality).