Mathematics 9709 · AS & A Level · Trigonometry

Trigonometry — practice question

(i)[3]

Express $8\sin\theta + 15\cos\theta$ in the form $R\sin(\theta + \alpha)$, where $R > 0$ and $0^\circ < \alpha < 90^\circ$. State the value of $\alpha$ correct to 2 decimal places.

(ii)[4]

Hence solve $8\sin\theta + 15\cos\theta = 6$ in the interval $0^\circ \leq \theta \leq 360^\circ$.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: State or indicate $R=17$

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