Mathematics 9709 · AS & A Level · Trigonometry

Trigonometry — practice question

(a)[4]

Show that the identity $4\sin(\theta + \frac{1}{3}\pi)\cos(\theta - \frac{1}{3}\pi) = \sqrt{3} + 2\sin 2\theta$ is true.

(b)[2]

Determine the exact value of $4\sin \frac{17\pi}{24}\cos \frac{\pi}{24}$.

(c)[4]

Find the exact value of $\int_{0}^{\frac{1}{8}\pi} 4\sin(2x + \frac{1}{3}\pi)\cos(2x - \frac{1}{3}\pi)\, dx$.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Obtain at least one of $\left(\tfrac12\sin\theta + \tfrac12\sqrt3\cos\theta\right)$ or $\left(\tfrac12\cos\theta + \tfrac12\sqrt3\sin\theta\right)$

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