CSEC ADDITIONAL MATHEMATICS · SECTION 3 · LESSON C6

Integration: Antiderivatives and Standard Integrals

Integration as the reverse of differentiation, indefinite integrals and the constant of integration, the rules, integrating powers, (ax + b)ⁿ and trigonometric functions.

Introductory CalculusS3 B.1S3 B.2S3 B.3S3 B.4S3 B.5S3 B.6≈ 45 min🎮 3 games
Before you start

By the end of this lesson you can…

Step 1 · Watch

Explainer video

5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.

LESSON C6 · EXPLAINER

Integration: Antiderivatives and Standard Integrals

Differentiate and you lose the constant. Integrate and you must put it back. Integration is just differentiation run backwards — and checking is always possible.

Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.

Step 2 · Read

Key notes

Copy these into your notebook in your own words — that is how they stick.

Antiderivative

If F′(x) = f(x) then ∫ f(x) dx = F(x) + C.

Power rule

∫ xⁿ dx = xⁿ⁺¹/(n + 1) + C, n ≠ −1.

Linear rules

∫ cf dx = c∫f dx; ∫(f ± g) dx = ∫f dx ± ∫g dx.

Linear bracket

∫ (ax + b)ⁿ dx = (ax + b)ⁿ⁺¹/[a(n + 1)] + C.

Trigonometric

∫ sin px dx = −cos px/p + C; ∫ cos qx dx = sin qx/q + C.

Constant

C represents a family of functions differing by constants.

Rewrite first

Roots and reciprocals as powers; expand products.

Check

Differentiate the answer.

EXAM TIPS & COMMON MISTAKES

  • Never forget + C on an indefinite integral.
  • For (ax + b)ⁿ divide by a as well as n + 1.
  • ∫ cos x dx = + sin x but ∫ sin x dx = − cos x: watch the sign.
  • Rewrite 1/x² and √x as powers before integrating.
Play & practise

Games

3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness. More games in the Additional Mathematics Arcade.

Step 3 · Practise

Paper 1 practice — multiple choice

8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.

CSEC Paper 01 style · SO B.4

1. ∫ (3x² − 4x + 5) dx is equal to

Answer: D. Power rule term by term.
CSEC Paper 01 style · SO B.4

2. ∫ √x dx is equal to

Answer: A. x^{3/2}/(3/2).
CSEC Paper 01 style · SO B.4

3. ∫ 1/x² dx is equal to

Answer: B. ∫ x⁻² dx = −x⁻¹.
Adapted from CSEC P1 May/June 2024 (integral of a linear bracket item)

4. If c is a constant, ∫ (2x + 1)³ dx is equal to

Answer: C. Divide by 4 and by 2.
Adapted from CSEC P1 May/June 2024 (trigonometric integral item)

5. If c is a constant, ∫ (sin x + 2 cos x) dx is equal to

Answer: D. −cos x + 2 sin x.
CSEC Paper 01 style · SO B.6

6. ∫ 3 sin 2x dx is equal to

Answer: A. −(1/2)(3) cos 2x.
CSEC Paper 01 style · SO B.5

7. ∫ (5 − 2x)⁴ dx is equal to

Answer: B. Divide by (−2)(5) = −10.
CSEC Paper 01 style · SO B.3

8. Which statement about ∫ f(x) dx is TRUE?

Answer: C. The constant C is arbitrary.
Step 4 · Apply

Paper 2 practice — structured questions

Write full answers, then reveal the mark scheme and tick the points you earned (24 marks in total). Show all your working — method marks count. Your answers are saved on this device.

CSEC Paper 02 style · Section 3 (Integration)

Question 1 [13 marks]

Find each of the following, where C is an arbitrary constant.

(a) ∫ (4x³ − 6x + 5) dx [2]

MARK SCHEME — (a) (max 2)

(b) ∫ (√x + 3/x²) dx [3]

MARK SCHEME — (b) (max 3)

(c) ∫ (2x + 1)³ dx [3]

MARK SCHEME — (c) (max 3)

(d) ∫ (3 sin 2x − 4 cos x) dx [3]

MARK SCHEME — (d) (max 3)

(e) Show, by differentiation, that your answer to part (c) is correct. [2]

MARK SCHEME — (e) (max 2)

CSEC Paper 02 style · Section 3 (Integration practice)

Question 2 [11 marks]

Find each integral.

(a) ∫ (5 − 2x)⁴ dx [3]

MARK SCHEME — (a) (max 3)

(b) ∫ (sin 4x + cos(x/2)) dx [3]

MARK SCHEME — (b) (max 3)

(c) ∫ x(x² + 1) dx [3]

MARK SCHEME — (c) (max 3)

(d) Explain why the answer to an indefinite integral must include a constant C. [2]

MARK SCHEME — (d) (max 2)

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Sources

Where this topic appears in CSEC papers

Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.