Mathematics 9709 · AS & A Level · Integration

Integration — practice question

Take $I = \displaystyle\int_{\frac{1}{4}}^{\frac{3}{4}} \sqrt{\dfrac{x}{1 - x}}\, dx$.
(i)[4]

With the substitution $x = \cos^2 \theta$, establish that $I = \displaystyle\int_{\frac{\pi}{6}}^{\frac{\pi}{3}} 2\cos^2 \theta\, d\theta$.

(ii)[4]

Therefore determine the exact value of $I$.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: Write down or infer $dx=-2\cos\theta\sin\theta\,d\theta$, or an equivalent form

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