Mathematics 9709 · AS & A Level · Trigonometry

Trigonometry — practice question

The reflex angle $\theta$ satisfies $\cos\theta = k$, where $0 \le k \le 1$.
(a)[2]

Determine an expression for $\sin\theta$ in terms of $k$.

(b)[1]

Find an expression for $\tan\theta$ in terms of $k$.

(ii)[2]

Explain why $\sin 2\theta$ is less than 0 when $0 \le k \le 1$.

Worked solution & mark scheme

This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Applies the identity $\sin^2\theta=1-\cos^2\theta$” …

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