Pearson Edexcel · A-Level · Mathematics
Course version: 9MA0 · Version from Mar 2026
Integrate xⁿ (excluding n = −1) and related sums, differences and constant…
Full specification wording
Integration: 8.2 Integrate xⁿ (excluding n = −1) and related sums, differences and constant multiples. Integrate e^(kx), 1/x, sin kx, cos kx and related sums, differences and constant multiples.
Standard integration reverses standard differentiation.
Checked against the Pearson Edexcel 9MA0 specification (opens in a new tab) on .
- Point 2 of 8
- 3 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Standard integration reverses standard differentiation. For powers, ∫ xⁿ dx = x^(n+1)/(n+1) + c, valid for all n except n = −1; for example ∫ x³ dx = x⁴/4 + c. The exceptional case is ∫ 1/x dx = ln|x| + c, where the modulus keeps the logarithm defined for negative x. Exponential functions integrate to themselves with a scale factor: ∫ e^(kx) dx = (1/k)e^(kx) + c. Trigonometric functions give ∫ sin kx dx = −(1/k)cos kx + c and ∫ cos kx dx = (1/k)sin kx + c. Sums, differences and constant multiples are integrated term by term, so ∫ (3x² − 2 sin 2x + 5/x) dx = x³ + cos 2x + 5 ln|x| + c.
What earns the marks
- Applies the power rule ∫ xⁿ dx = x^(n+1)/(n+1) + c correctly for positive, negative and fractional n except n = −1.
- Recognises the exceptional case and integrates 1/x as ln|x| + c rather than using the power rule.
- Integrates e^(kx) as (1/k)e^(kx) + c, including the reciprocal scale factor.
- Integrates sin kx as −(1/k)cos kx + c and cos kx as (1/k)sin kx + c with correct signs.
- Integrates sums, differences and constant multiples term by term, carrying the constant of integration c.
- Simplifies coefficients and exponents correctly, for example writing x^(5/2)/(5/2) as (2/5)x^(5/2).
Common mistakes and how to put them right
Applying the power rule to 1/x and obtaining x⁰/0.
Put it right by using ln|x| + c instead.
Forgetting the reciprocal factor when integrating e^(kx) or trigonometric functions.
Put it right by dividing by k.
Omitting the constant of integration in an indefinite integral.
Put it right by adding c to every indefinite result.
Exam tips
- Write each term on its own line before combining, so signs and coefficients are easy to check.
- Differentiate your answer mentally to confirm it returns the original integrand.
- Remember the modulus in ln|x| and the constant c in every indefinite integral.
Try the lesson
The start of the Integration: 8.2 Integrate xⁿ (excluding n = −1) and related sums, differences and constant multiples. Integrate e^(kx), 1/x, sin kx, cos kx and related sums, differences and constant multiples. lesson, made from checked teaching notes for this specification point.
Have a go first
Find the indefinite integral of x⁵ with respect to x.
Listen
Standard integration reverses standard differentiation. For powers, ∫ xⁿ dx = x^(n+1)/(n+1) + c, valid for all n except n = −1; for example ∫ x³ dx = x⁴/4 + c. The exceptional case is ∫ 1/x dx = ln|x| + c, where the modulus keeps the logarithm defined for negative x. Exponential functions integrate to themselves with a scale factor: ∫ e^(kx) dx = (1/k)e^(kx) + c. Trigonometric functions give ∫ sin kx dx = −(1/k)cos kx + c and ∫ cos kx dx = (1/k)sin kx + c. Sums, differences and constant multiples are integrated term by term, so ∫ (3x² − 2 sin 2x + 5/x) dx = x³ + cos 2x + 5 ln|x| + c. A strong answer earns marks for these points. Applies the power rule ∫ xⁿ dx = x^(n+1)/(n+1) + c correctly for positive, negative and fractional n except n = −1. Recognises the exceptional case and integrates 1/x as ln|x| + c rather than using the power rule. Integrates e^(kx) as (1/k)e^(kx) + c, including the reciprocal scale factor. Integrates sin kx as −(1/k)cos kx + c and cos kx as (1/k)sin kx + c with correct signs. A common slip: Applying the power rule to 1/x and obtaining x⁰/0. Instead, using ln|x| + c instead. Exam tip: Write each term on its own line before combining, so signs and coefficients are easy to check.
See it
Key words
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Standard integrals as inverses of derivatives
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The exceptional case of 1/x
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Term-by-term integration of sums and differences
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See every definition
- Standard integrals as inverses of derivatives
- Standard integration reverses standard differentiation, so powers, exponentials and trigonometric functions integrate back to related standard forms.
- The exceptional case of 1/x
- The power rule is valid for all n except n = −1, where 1/x integrates as ln|x| + c instead.
- Term-by-term integration of sums and differences
- Sums, differences and constant multiples are integrated term by term, carrying the constant of integration c.
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