Mathematics 9709 · AS & A Level · Trigonometry

Trigonometry — practice question

(a(i))[3]

Express $4\sin\theta + 4\cos\theta$ as $R\sin(\theta + \alpha)$, with $R > 0$ and $0^\circ < \alpha < 90^\circ$.

(a(ii))[2]

Hence determine the smallest positive value of $\theta$ that satisfies $4\sin\theta + 4\cos\theta = 5$.

(b)[6]

Solve the equation $4\cot 2x = 5 + \tan x$ for $0 < x < \pi$, showing all the working needed and giving the answers correct to 2 decimal places.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: State $R=\sqrt{32}$ or another equivalent value such as $5.657\ldots$.

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