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IB Mathematics: Applications and Interpretation HL · AHL 3: Further Integration · AHL 3.3

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Further integration: practice Problem set A

Show the substitution or the rule you use. Add + c to every indefinite integral. Use a boundary condition to find c. Give exact answers unless the question asks for 3 significant figures.

Difficulty: first skills applying them stretch

Skills

  1. \(\frac{dy}{dx}=15\sqrt{x}\), and y = 75 when x = 4. Find y in terms of x.

  2. Find the required function in each case.

    1. (a) \(f'(x)=6\cos x-5\sin x\) and f(0) = 9. Find f(x).
    2. (b) \(\frac{dy}{dx}=3e^x+\frac{4}{x}\) for x > 0, and y = 2 when x = 1. Find y in terms of x.
    3. (c) \(\int\frac{9x^2+4}{3x}\,dx\)
  3. Find each integral.

    1. (a) \(\int(7-3x)^{8}\,dx\)
    2. (b) \(\int(3\sin(4x)+8\cos(2x))\,dx\)
    3. (c) \(\int 6x(x^2+3)^{4}\,dx\)
  4. Find each integral.

    1. (a) \(\int x^2\sqrt{5x^3+2}\,dx\)
    2. (b) \(\int x\sqrt[3]{7-2x^2}\,dx\)
  5. Find each integral.

    1. (a) \(\int 9xe^{6x^2}\,dx\)
    2. (b) \(\int 8x^2e^{-2x^3}\,dx\)
  6. Find each integral.

    1. (a) \(\int\frac{x^2}{2x^3+9}\,dx\)
    2. (b) \(\int\frac{x^3}{1-x^4}\,dx\)
  7. Use a substitution to find the following.

    1. (a) \(\frac{dy}{dx}=x\sin(5x^2)\). Find y in terms of x.
    2. (b) \(\int\frac{4x}{\sqrt{2x^2+9}}\,dx\)

In context

  1. Water flows into a tank. After t minutes the volume of water is V litres, and \(\frac{dV}{dt}=0.6t^2+2\) and V = 15 when t = 0.

    1. (a) Find an expression for \(V\) in terms of t.
    2. (b) Find the volume when t = 5.
  2. The height of a drone above the ground is x metres at time t seconds, and \(\frac{dx}{dt}=12-5e^t\) and x = 8 when t = 0.

    1. (a) Find an expression for \(x\) in terms of t.
    2. (b) Find the height when t = 1.5.

Stretch

  1. Find f(x) in each case.

    1. (a) \(f'(x)=\frac{3}{(2x+1)^2}\), and the graph of y = f(x) passes through the point (1, 0). Find f(x).
    2. (b) \(f'(x)=\frac{5\ln x}{2x}\) for x > 0, and the curve y = f(x) passes through the point \((e, 3)\). Find f(x).
  2. \(f'(x)=\frac{3}{x}\) and f(-2) = 4. Find the exact value of \(f(-5)\).

  3. Find each integral.

    1. (a) \(\int\left(8\sin^3 x\cos x+kx^{3}+2\right)dx\), where k is a constant.
    2. (b) \(\int\frac{e^{5x}-e^{-x}}{e^{2x}}\,dx\)
  4. Find each integral.

    1. (a) \(\int\sqrt{x^4+5x^2}\,dx\) for x > 0.
    2. (b) \(\int\frac{6}{x\ln x}\,dx\) for x > 1.
  5. Find each integral.

    1. (a) Given that \(\cos 2x=2\cos^2x-1\), find \(\int 6\cos^2x\,dx\).
    2. (b) \(\int\tan 3x\,dx\), showing your working.
    3. (c) \(\int 6\sin^3x\,dx\)

jmaths.xyz · AI HL · AHL 3.3 Further integration: substitution and boundary conditions