Mathematics 9709 · AS & A Level · Trigonometry

Trigonometry — practice question

(i)[3]

Prove the identity that $\sin(x - 30^{\circ}) + \cos(x - 60^{\circ}) = (\sqrt{3})\sin x$.

(ii)[6]

Hence solve the equation $\sin(x - 30^{\circ}) + \cos(x - 60^{\circ}) = \frac{1}{2}\sec x$, in the interval $0^{\circ} < x < 360^{\circ}$.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Use the correct $\sin(A-B)$ and $\cos(A-B)$ formulae

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