직선형 수요 곡선은 변하는 탄력성을 가집니다.
도입됨| English | 의미 |
|---|---|
| unitary elasticity/ˈjuːnɪtəri ɪlæˈstɪsɪti/ | 단위 탄력 |
| price elasticity of demand/praɪs ɪlæˈstɪsɪti ɒv dɪˈmænd/ | 가격 수요 탄력성 |
A decision you can investigate
- A seller sees a straight demand line and assumes responsiveness must be constant.
- The same change in units is a different percentage of a large or small starting quantity.
Build the explanation
- PED is percentage quantity-demanded change divided by percentage own-price change. Interpret absolute magnitude: 0 perfectly inelastic, below 1 inelastic, 1 unitary, above 1 elastic; perfectly elastic demand is the horizontal limiting case. For a linear demand curve, a constant units-per-price slope does not imply constant PED.
- With Q = 100−2P, local PED = −2 × P/Q. The ratio changes along the line. Substitutes, branding, expenditure share, addiction and durability affect responsiveness; durable goods can allow postponement, while strong attachment can limit switching.
Work through the evidence
- At P=10, Q=80: local PED=−2 × 10/80=−0.25; TR=P × Q=800. At P=25, Q=50: local PED=−1 and TR=1250. At P=40, Q=20: local PED=−4 and TR=800.
- Below the midpoint, a small price rise increases revenue; above it, a small price cut increases revenue. The midpoint is the maximum of TR in this particular linear model. A point elasticity is local: it is not a claim that a large finite change has exactly the same percentage ratio.
P=40이고 Q=20일 때 현지 가격 탄력성(PED)은 얼마입니까?
난이도 1/5 · 100 코인 + 오늘 첫 완료 시 소액 보너스
현지 식은 −2 × 40/20 = −4입니다.
제시된 점들 중 가장 큰 수익을 가지는 점은 어디입니까?
난이도 1/5 · 100 코인 + 오늘 첫 완료 시 소액 보너스
1250이 두 가지 revenue(800)보다 큽니다.
탄력도가 1로 반올림된 현지 값은 모든 큰 가격 변동에 대해 수익이 변하지 않음을 보장합니다.
난이도 1/5 · 100 코인 + 오늘 첫 완료 시 소액 보너스
점 추정치는 현지적이며, 유한한 변화에 대한 실제 가격과 수량 값을 확인해야 합니다.
Test the limits
- Unitary elasticity 单位弹性 implies no first-order revenue effect locally; revenue over a finite interval must be checked as P × Q, rather than assuming unchanged revenue from a rounded estimate. Profit also depends on costs.
- A slope comparison needs the same axis scales, and even then the price/quantity point matters. Taxes on addictive products may reduce quantity little over a short period while raising spending; the policy aim and distribution still matter.
왜 일정한 기울기가 일정한 PED를 보장하지 않습니까?
난이도 1/5 · 100 코인 + 오늘 첫 완료 시 소액 보너스
기준값은 선상에서 달라집니다.
Apply and explain your answer
- Why is demand more elastic at price 40 than at price 10 in this same model?
- The constant slope is multiplied by a larger price-to-quantity ratio: 40/20 versus 10/80.
용어를 의미와 매칭하십시오.
난이도 2/5 · 140 코인 + 오늘 첫 완료 시 소액 보너스
각 용어를 명시된 경제적 관계에 따라 사용하라.
Use the terms precisely
- price elasticity of demand 需求价格弹性: Percentage quantity-demanded response relative to percentage own-price change.
- unitary elasticity: The magnitude of percentage quantity response equals the percentage stimulus.
At P=10, Q=80: local PED=−2 × 10/80=−0.25; TR=P × Q=800. At P=25, Q=50: local PED=−1 and TR=1250. At P=40, Q=20: local PED=−4 and TR=800. Below the midpoint, a small price rise increases revenue; above it, a small price cut increases revenue. The midpoint is the maximum of TR in this particular linear model. A point elasticity is local: it is not a claim that a large finite change has exactly the same percentage ratio.
Unitary elasticity implies no first-order revenue effect locally; revenue over a finite interval must be checked as P × Q, rather than assuming unchanged revenue from a rounded estimate. Profit also depends on costs. A slope comparison needs the same axis scales, and even then the price/quantity point matters. Taxes on addictive products may reduce quantity little over a short period while raising spending; the policy aim and distribution still matter.
PED is percentage quantity-demanded change divided by percentage own-price change. Interpret absolute magnitude: 0 perfectly inelastic, below 1 inelastic, 1 unitary, above 1 elastic; perfectly elastic demand is the horizontal limiting case. For a linear demand curve, a constant units-per-price slope does not imply constant PED.