(i)[3]
Show that $\frac{\cos 2x + 9\cos x + 5}{\cos x + 4} = 2\cos x + 1$.
(ii)[4]
Hence determine the exact value of $\int_{-\pi}^{\pi} \frac{\cos 4x + 9\cos 2x + 5}{\cos 2x + 4}\,dx$.
Mathematics 9709 · AS & A Level · Integration
Integration — practice question
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Substitute $\cos 2x = 2\cos^2 x - 1$ and try to factorise the numerator” …
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