A-level · Integration

Integration by reversing the chain ruleExam-style questions

Integrating by recognition — spotting the chain rule's fingerprint, the derivative of an inside function sitting as a factor. A power of a function; adjusting the answer when the factor is a number out; the log case, when the top is the derivative of the bottom; exponential and trig insides; and how to tell when recognition fails and you need to expand or substitute.

19 questions · A-level level · mark scheme and worked solution on each · no sign-up to try

DifficultyAllLevel 2Level 3Level 4Level 5
  1. 1
    (a) Find ddx(5−2x2)4\dfrac{d}{dx}\left(5 - 2x^2\right)^4

    (2 marks)
    (b) Hence show that

    ∫01x(5−2x2)3dx=R\int_0^1 x\left(5 - 2x^2\right)^3 dx = R

    where RR is an integer to be found.

    (Solutions relying on calculator technology are not acceptable.)

    (3 marks)
    Level 3 · 5 marksTry it
  2. 2
    Find ∫xx2+5 dx\displaystyle\int x\sqrt{x^2 + 5}\,dx.
    Level 3 · 2 marksTry it
  3. 3
    Find ∫x ex2 dx\displaystyle\int x\,e^{x^2}\,dx.
    Level 3 · 2 marksTry it
  4. 4
    Find ∫cos⁡x esin⁡x dx\displaystyle\int \cos x\,e^{\sin x}\,dx.
    Level 3 · 2 marksTry it
  5. 5
    Find ∫2x+3x2+3x+1 dx\displaystyle\int \frac{2x + 3}{x^2 + 3x + 1}\,dx.
    Level 3 · 2 marksTry it

9 more questions on integration by reversing the chain rule

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