Mathematics 9709 · AS & A Level · Trigonometry

Trigonometry — practice question

(a)[3]

Rewrite $4\cos \theta + 3\sin \theta$ as $R\cos(\theta - \alpha)$, with $R > 0$ and $0 < \alpha < \frac{1}{2}\pi$. State the value of $\alpha$ correct to 4 decimal places.

(b(i))[4]

Hence determine the solutions of the equation $4\cos \theta + 3\sin \theta = 2$ for $0 < \theta < 2\pi$.

(b(ii))[3]

Hence evaluate $\int \frac{50}{(4\cos \theta + 3\sin \theta)^2} \, d\theta$.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: State or show that $R=5$

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