Supported HL focus. First assessment 2021; current through 2028. First-assessment-2029 course is separate.. Remaining guide, assessment and practical requirements retain their recorded holds.
Prerequisites: read the stated quantities and units, use arithmetic and the model conditions below. Each lesson develops its own method before independent transfer.
These are original or explicitly fictional teaching examples, not actual measurements or completed assessed learner investigations.
1.2
Exact arithmetic and estimation
English
Can we pack without leftovers?
A supplier packs 72 pencils and 90 pens into identical gift bags. How can we avoid leftovers?
This lesson studies prime factor 质因数: A prime number that divides the integer exactly.
Choose the mathematical structure
Prime factors reveal shared structure. Use the smallest common prime powers for the HCF and the largest for the LCM. Estimate before calculating; use brackets to preserve the order of operations.
State the allowed inputs and units before calculating. An equation should express the relationship, not just record a calculator entry.
Check the result against the starting quantities. Substitute into the original relation, or compare the graph and numerical answer where appropriate.
Example:
72=2^3×3^2 and 90=2×3^2×5. Their HCF is 2×9=18. Make 18 bags with 4 pencils and 5 pens each. Their LCM is 2^3×3^2×5=360.
Test a tempting shortcut
The HCF divides both numbers; the LCM is a multiple of both. They answer different questions. A decimal estimate is not an exact fraction.
When a shortcut fails, identify the assumption it breaks. Keep an exact value until the requested final rounding.
Warn:
The HCF of two positive integers is always larger than either integer. This claim is false. Explain which definition or assumption it violates.
Interpret a new situation
For a non-calculator paper, keep fractions exact and show cancellation. For a calculator paper, enter the full expression and compare with your estimate.
A complete solution gives the mathematical result and explains what it means. Check that it is possible in the stated context.
Use this in your course
Current first-assessment-2021 Analysis and Approaches HL. This is authored concept support; the full guide is needed to certify every objective.
Give the method before the final answer, and use the paper's calculator and formula rules. Review a wrong answer by locating the first invalid step.
Key:
A prime number that divides the integer exactly. Choose the relationship, show the method, check its assumptions and interpret the result.
A microscope records a length of 0.000072 metres. A compact representation must keep its size correct.
This lesson studies index 指数: The power to which a base is raised.
Choose the mathematical structure
For the same positive base, multiplication adds indices and division subtracts them. A negative index means reciprocal; a fractional index represents a root. Standard form has 1≤a<10.
State the allowed inputs and units before calculating. An equation should express the relationship, not just record a calculator entry.
A saving plan adds ¥30 more each week; a population model grows by 5% each year. Equal differences and equal ratios need different models.
This lesson studies common ratio 公比: The constant multiplier 乘数 between consecutive terms of a geometric sequence.
Choose the mathematical structure
For an arithmetic progression, u_n=a+(n-1)d and S_n=n(2a+(n-1)d)/2. For a geometric progression, u_n=ar^(n-1) and S_n=a(1-r^n)/(1-r). An infinite geometric sum exists only if |r|<1.
State the allowed inputs and units before calculating. An equation should express the relationship, not just record a calculator entry.
Check the result against the starting quantities. Substitute into the original relation, or compare the graph and numerical answer where appropriate.
Example:
For a=5,d=3,n=8, u_8=5+7×3=26 and S_8=8(10+21)/2=124. For a=12,r=1/2, S infinity=12/(1-1/2)=24. For u_(n+1)=2u_n+1 with u_1=1, the next terms are 3,7,15.
Test a tempting shortcut
The first term has index 1, so the exponent is n-1. A sequence is a list; a series is a sum. A geometric sequence can alternate in sign and still converge.
When a shortcut fails, identify the assumption it breaks. Keep an exact value until the requested final rounding.
Warn:
Every geometric series has a finite sum to infinity. This claim is false. Explain which definition or assumption it violates.
Interpret a new situation
Explain whether the context justifies additive or multiplicative change. In finance, distinguish a single deposit from a stream of deposits before choosing a sum formula.
A complete solution gives the mathematical result and explains what it means. Check that it is possible in the stated context.
Use this in your course
Current first-assessment-2021 Analysis and Approaches HL. This is authored concept support; the full guide is needed to certify every objective.
Give the method before the final answer, and use the paper's calculator and formula rules. Review a wrong answer by locating the first invalid step.
Key:
The constant multiplier between consecutive terms of a geometric sequence. Choose the relationship, show the method, check its assumptions and interpret the result.
A coat is reduced by 20% to ¥240. The discount applies to the original price, not to the sale price.
This lesson studies multiplier: A factor that performs a percentage change in one multiplication.
Choose the mathematical structure
A p% increase has multiplier 1+p/100; a decrease has multiplier 1-p/100. Reverse a percentage by dividing by the multiplier. In a ratio, first find the total number of parts.
State the allowed inputs and units before calculating. An equation should express the relationship, not just record a calculator entry.
Check the result against the starting quantities. Substitute into the original relation, or compare the graph and numerical answer where appropriate.
Example:
Let the original price be P. The model is sale price=0.8P. Hence P=240/0.8=300. A later 20% increase gives 240×1.2=288, so the two changes do not cancel.
Test a tempting shortcut
A percentage uses a stated base. Subtracting the percentages loses that base. For compound change, multiply the multipliers; do not add the percentages.
When a shortcut fails, identify the assumption it breaks. Keep an exact value until the requested final rounding.
Warn:
A 20% decrease followed by a 20% increase restores the starting price. This claim is false. Explain which definition or assumption it violates.
Interpret a new situation
For direct proportion use y=kx; for inverse proportion use y=k/x. Calculate k from a known pair before using a new value. State what you held constant.
A complete solution gives the mathematical result and explains what it means. Check that it is possible in the stated context.
Use this in your course
Current first-assessment-2021 Analysis and Approaches HL. This is authored concept support; the full guide is needed to certify every objective.
Give the method before the final answer, and use the paper's calculator and formula rules. Review a wrong answer by locating the first invalid step.
Key:
A factor that performs a percentage change in one multiplication. Choose the relationship, show the method, check its assumptions and interpret the result.
1.6
จำนวนเชิงซ้อนและราก
English
What if the root is not real?
The equation x²+1=0 has no real roots. Extending the number system lets us represent and calculate with both roots.
This lesson studies complex conjugate 共轭复数: The number obtained by reversing the sign of the imaginary part.
Choose the mathematical structure
Write z=a+bi with i²=-1. The conjugate is a-bi and z times its conjugate=a²+b². The modulus is √(a²+b²); the argument needs the correct quadrant. Conjugate roots occur for polynomials with real coefficients.
State the allowed inputs and units before calculating. An equation should express the relationship, not just record a calculator entry.
Check the result against the starting quantities. Substitute into the original relation, or compare the graph and numerical answer where appropriate.
Example:
For z=3+4i, |z|=5 and z conjugate=3-4i. The reciprocal is (3-4i)/25. For x²-6x+13=0, the roots are 3±2i. Multiplying by the conjugate makes a complex denominator real.
Test a tempting shortcut
The square root of a sum is not the sum of the square roots. An inverse tangent alone may return the wrong quadrant. Do not confuse modulus with squared modulus.
When a shortcut fails, identify the assumption it breaks. Keep an exact value until the requested final rounding.
Warn:
For a+bi, its modulus is always a+b. This claim is false. Explain which definition or assumption it violates.
Interpret a new situation
Draw the real axis horizontally and imaginary axis vertically. For products, moduli multiply and arguments add; powers extend this geometric pattern through de Moivre's theorem.
A complete solution gives the mathematical result and explains what it means. Check that it is possible in the stated context.
Use this in your course
Current first-assessment-2021 Analysis and Approaches HL. This is authored concept support; the full guide is needed to certify every objective.
Give the method before the final answer, and use the paper's calculator and formula rules. Review a wrong answer by locating the first invalid step.
Key:
The number obtained by reversing the sign of the imaginary part. Choose the relationship, show the method, check its assumptions and interpret the result.
A small measurement change affects a power of a quantity. An expansion can show the size of first and second effects.
This lesson studies binomial coefficient 二项式系数: The number of ways to choose a specified number of objects from a set.
Choose the mathematical structure
For positive integer n, (a+b)^n is a finite binomial expansion. For noninteger n, expand (1+x)^n as 1+nx+n(n-1)x²/2+... with |x|<1. Factor out constants before using this form.
State the allowed inputs and units before calculating. An equation should express the relationship, not just record a calculator entry.
Work through a checked case
$$(1+x)^n=1+nx+\frac{n(n-1)}{2}x^2+\cdots$$
Check the result against the starting quantities. Substitute into the original relation, or compare the graph and numerical answer where appropriate.
Example:
(1+2x)^5=1+10x+40x²+80x³+80x⁴+32x⁵. For (1+x)^(-1), the first three terms are 1-x+x²; at x=0.1 this gives 0.91 versus the exact 1/1.1≈0.909091.
Test a tempting shortcut
An expansion in 2x requires |2x|<1 for the infinite series, not merely |x|<1. Positive-integer expansions are finite and do not have that convergence restriction.
When a shortcut fails, identify the assumption it breaks. Keep an exact value until the requested final rounding.
Warn:
Every binomial expansion is a finite polynomial, including powers that are not positive integers. This claim is false. Explain which definition or assumption it violates.
Interpret a new situation
State the range of validity alongside an approximation. Retain enough terms to support the requested accuracy, and distinguish a coefficient from the whole term containing x.
A complete solution gives the mathematical result and explains what it means. Check that it is possible in the stated context.
Use this in your course
Current first-assessment-2021 Analysis and Approaches HL. This is authored concept support; the full guide is needed to certify every objective.
Give the method before the final answer, and use the paper's calculator and formula rules. Review a wrong answer by locating the first invalid step.
Key:
The number of ways to choose a specified number of objects from a set. Choose the relationship, show the method, check its assumptions and interpret the result.
Near a known point, a complicated function can be replaced by a polynomial approximation. The approximation needs a centre and a valid scale.
This lesson studies Taylor polynomial 泰勒多项式: A polynomial formed from a function's derivatives at a chosen centre.
Choose the mathematical structure
About x=a, f(x)=f(a)+f prime(a)(x-a)+f double prime(a)(x-a)²/2!+... when the expansion is valid. At a=0 it is a Maclaurin expansion. Finite sums may also simplify by cancellation or standard sum formulae.
State the allowed inputs and units before calculating. An equation should express the relationship, not just record a calculator entry.
Check the result against the starting quantities. Substitute into the original relation, or compare the graph and numerical answer where appropriate.
Example:
The first three terms of e^x are 1+x+x²/2. At x=0.1 this gives 1.105, close to e^0.1≈1.105170. For the sum of k² from k=1 to 5, n(n+1)(2n+1)/6 gives 5×6×11/6=55.
Test a tempting shortcut
The factorial belongs in the denominator of every Taylor coefficient. The expansion centre is not always zero. An approximation close to its centre can be poor far away.
When a shortcut fails, identify the assumption it breaks. Keep an exact value until the requested final rounding.
Warn:
A Taylor polynomial is always exact for the original function at every input. This claim is false. Explain which definition or assumption it violates.
Interpret a new situation
For a telescoping series, write several terms and identify both surviving ends. For a Taylor approximation, state its order and compare with a known value or a remainder estimate where required.
A complete solution gives the mathematical result and explains what it means. Check that it is possible in the stated context.
Use this in your course
Current first-assessment-2021 Analysis and Approaches HL. This is authored concept support; the full guide is needed to certify every objective.
Give the method before the final answer, and use the paper's calculator and formula rules. Review a wrong answer by locating the first invalid step.
Key:
A polynomial formed from a function's derivatives at a chosen centre. Choose the relationship, show the method, check its assumptions and interpret the result.
ระบุ domain และ range สำหรับฟังก์ชันกลับกัน ต้องตรวจสอบก่อนว่าฟังก์ชันนั้นเป็น one-to-one บนโดเมน Composition fg หมายถึงนำ g ไปใช้ก่อน แล้วจึงนำ f ไปใช้ ผลลัพธ์กลางต้องเป็นค่าอินพุกที่ f อนุญาตให้ใช้
ค่า Screening Inverse ของเครื่องคิดเลขให้ค่าหลักเพียงค่าเดียว มันไม่ได้ให้คำตอบทุกชุด การหารด้วย sin x อาจทำให้หายคำตอบที่ sin x=0; ให้ตรวจสอบกรณีนี้ก่อน
Supported HL focus. First assessment 2021; current through 2028. First-assessment-2029 course is separate.. Remaining guide, assessment and practical requirements retain their recorded holds.
Prerequisites: read the stated quantities and units, use arithmetic and the model conditions below. Each lesson develops its own method before independent transfer.
These are original or explicitly fictional teaching examples, not actual measurements or completed assessed learner investigations.
5.2
อนุพันธ์และจุดคงที่
English
What is the slope at one point?
A curved road has different slopes at different positions. An average gradient cannot describe every point.
This lesson studies derivative 导数: The instantaneous rate of change, also the gradient of a tangent.
Choose the mathematical structure
For y=ax^n, dy/dx=anx^(n-1). A stationary point satisfies dy/dx=0. Check the sign change of the derivative, or the second derivative when it is nonzero, to classify it.
State the allowed inputs and units before calculating. An equation should express the relationship, not just record a calculator entry.
Check the result against the starting quantities. Substitute into the original relation, or compare the graph and numerical answer where appropriate.
Example:
For y=x³-3x, dy/dx=3x²-3. At x=1, the gradient is 0 and y=-2. The second derivative is 6x, positive at x=1, so this is a local minimum. At x=-1, y=2 and the second derivative is negative, giving a local maximum.
Test a tempting shortcut
A zero derivative does not always mean a maximum or minimum: y=x³ is stationary at 0 but continues increasing. An endpoint can also produce an extreme value on a restricted domain.
When a shortcut fails, identify the assumption it breaks. Keep an exact value until the requested final rounding.
Warn:
Every point with zero derivative is a local maximum or minimum. This claim is false. Explain which definition or assumption it violates.
Interpret a new situation
At GCSE/IGCSE use only the polynomial scope allowed by the tier; do not add chain, product or quotient rules there. At advanced level, connect the derivative to rates and optimization with a valid domain.
A complete solution gives the mathematical result and explains what it means. Check that it is possible in the stated context.
Use this in your course
Current first-assessment-2021 Analysis and Approaches HL. This is authored concept support; the full guide is needed to certify every objective.
Give the method before the final answer, and use the paper's calculator and formula rules. Review a wrong answer by locating the first invalid step.
Key:
The instantaneous rate of change, also the gradient of a tangent. Choose the relationship, show the method, check its assumptions and interpret the result.
A velocity graph tells us motion at an instant. How can we recover the displacement accumulated over time?
This lesson studies antiderivative 原函数: A function whose derivative equals the given integrand.
Choose the mathematical structure
For n≠-1, the integral of ax^n is ax^(n+1)/(n+1)+C. A definite integral is signed accumulation. Split at sign changes when total area or distance is required.
State the allowed inputs and units before calculating. An equation should express the relationship, not just record a calculator entry.
Check the result against the starting quantities. Substitute into the original relation, or compare the graph and numerical answer where appropriate.
Example:
For v(t)=3t²-3 over 0≤t≤2, displacement=[t³-3t]_0^2=2. Since v changes sign at t=1, distance=-[t³-3t]_0^1+[t³-3t]_1^2=2+4=6. The constants cancel only for a definite integral.
Test a tempting shortcut
The integral of 1/x is ln|x|+C, not the power rule with n=-1. Signed area can be zero even when the total enclosed area is positive.
When a shortcut fails, identify the assumption it breaks. Keep an exact value until the requested final rounding.
Warn:
A definite integral always equals the total positive area, even when the graph crosses the axis. This claim is false. Explain which definition or assumption it violates.
Interpret a new situation
Identify what the integral means and include the correct units. A rate measured per second integrates to the underlying quantity, not to another rate. Differentiate an antiderivative to check it.
A complete solution gives the mathematical result and explains what it means. Check that it is possible in the stated context.
Use this in your course
Current first-assessment-2021 Analysis and Approaches HL. This is authored concept support; the full guide is needed to certify every objective.
Give the method before the final answer, and use the paper's calculator and formula rules. Review a wrong answer by locating the first invalid step.
Key:
A function whose derivative equals the given integrand. Choose the relationship, show the method, check its assumptions and interpret the result.
Check the result against the starting quantities. Substitute into the original relation, or compare the graph and numerical answer where appropriate.
Example:
For y=(3x+1)^4, y prime=4(3x+1)^3×3=12(3x+1)^3. At x=0, the gradient is 12. For x²+y²=25, differentiate implicitly: 2x+2y y prime=0, so y prime=-x/y when y≠0.
Test a tempting shortcut
A derivative of a product is not the product of the derivatives. In implicit differentiation, every differentiated function of y brings a dy/dx factor. A quotient's denominator is squared.
When a shortcut fails, identify the assumption it breaks. Keep an exact value until the requested final rounding.
Warn:
The derivative of u(x)v(x) is always u prime times v prime. This claim is false. Explain which definition or assumption it violates.
Interpret a new situation
Choose a useful form before differentiating: expanding a short polynomial may be simpler. For related rates, write the relation in symbols, differentiate with respect to time, then substitute measured values.
A complete solution gives the mathematical result and explains what it means. Check that it is possible in the stated context.
Use this in your course
Current first-assessment-2021 Analysis and Approaches HL. This is authored concept support; the full guide is needed to certify every objective.
Give the method before the final answer, and use the paper's calculator and formula rules. Review a wrong answer by locating the first invalid step.
Key:
The rule that multiplies the outer derivative by the inner derivative for a composite function. Choose the relationship, show the method, check its assumptions and interpret the result.
A simple-looking product such as xe^x cannot be integrated by separately integrating each factor.
This lesson studies integration by parts 分部积分法: An integration method based on the derivative of a product.
Choose the mathematical structure
Use substitution when an inner derivative appears as a factor. By parts, integral u v prime =uv-integral u prime v. For a rational function, divide first if needed, then decompose into partial fractions.
State the allowed inputs and units before calculating. An equation should express the relationship, not just record a calculator entry.
Work through a checked case
$$\int u v^{\prime}\,dx=uv-\int u^{\prime}v\,dx$$
Check the result against the starting quantities. Substitute into the original relation, or compare the graph and numerical answer where appropriate.
Example:
For integral xe^x dx, take u=x and v prime=e^x. Then the integral is xe^x-e^x+C. For integral 2x/(x²+1) dx, substitute w=x²+1, dw=2x dx; the answer is ln(x²+1)+C.
Test a tempting shortcut
Choosing u and v prime well matters: the remaining integral should become simpler. In a definite substitution, either change the limits or return to x before applying the original limits.
When a shortcut fails, identify the assumption it breaks. Keep an exact value until the requested final rounding.
Warn:
The integral of a product equals the product of its separate integrals. This claim is false. Explain which definition or assumption it violates.
Interpret a new situation
Check by differentiating. For volumes of revolution around the x-axis use V=π integral y² dx; do not confuse the square of a function with the integral of the function.
A complete solution gives the mathematical result and explains what it means. Check that it is possible in the stated context.
Use this in your course
Current first-assessment-2021 Analysis and Approaches HL. This is authored concept support; the full guide is needed to certify every objective.
Give the method before the final answer, and use the paper's calculator and formula rules. Review a wrong answer by locating the first invalid step.
Key:
An integration method based on the derivative of a product. Choose the relationship, show the method, check its assumptions and interpret the result.
A growing population's rate is proportional to its current size. The rate equation describes a whole family until an initial population is supplied.
This lesson studies initial condition 初始条件: A specified value that selects a particular solution from a family.
Choose the mathematical structure
For dy/dx=ky, separate variables: dy/y=k dx, giving y=Ae^(kx). Use an initial condition to find A. Euler's method takes y next=y+h f(x,y), with a chosen step h.
State the allowed inputs and units before calculating. An equation should express the relationship, not just record a calculator entry.
Work through a checked case
$$\frac{dy}{dx}=ky,\qquad y=Ae^{kx}$$
Check the result against the starting quantities. Substitute into the original relation, or compare the graph and numerical answer where appropriate.
Example:
With dy/dx=0.5y and y(0)=2, y=2e^(0.5x). Euler with h=0.2 gives y(0.2)≈2+0.2×1=2.2 and y(0.4)≈2.2+0.2×1.1=2.42. The exact second value is about 2.4428.
Test a tempting shortcut
An initial condition determines the integration constant; it is not a replacement for integrating. Dividing by y can omit an equilibrium solution y=0. Euler accuracy depends on step size and the equation.
When a shortcut fails, identify the assumption it breaks. Keep an exact value until the requested final rounding.
Warn:
Every step size gives exactly the same Euler approximation. This claim is false. Explain which definition or assumption it violates.
Interpret a new situation
For second-order linear equations, combine the complementary function with an appropriate particular integral, then apply the required initial conditions. This is Further Pure scope; check the named unit.
A complete solution gives the mathematical result and explains what it means. Check that it is possible in the stated context.
Use this in your course
Current first-assessment-2021 Analysis and Approaches HL. This is authored concept support; the full guide is needed to certify every objective.
Give the method before the final answer, and use the paper's calculator and formula rules. Review a wrong answer by locating the first invalid step.
Key:
A specified value that selects a particular solution from a family. Choose the relationship, show the method, check its assumptions and interpret the result.
การสำรวจทางคณิตศาสตร์ภายใต้การดูแลของโรงเรียนสามารถถูกแทนที่ด้วยการทดสอบ模擬 (mock exam) แบบเขียน限时 This claim is false. อธิบายว่ามันละเมิดนิยามหรือสมมติฐานใด