Mathematics 9709 · AS & A Level · Trigonometry

Trigonometry — practice question

(i)[3]

Rewrite $(\sqrt{6})\cos \theta + (\sqrt{10})\sin \theta$ in the form $R\cos(\theta - \alpha)$, where $R > 0$ and $0^\circ < \alpha < 90^\circ$. State the value of $\alpha$ correct to 2 decimal places.

(ii(a))[2]

Hence, determine the least positive angle $\theta$ satisfying $(\sqrt{6})\cos \theta + (\sqrt{10})\sin \theta = -4$.

(ii(b))[4]

Hence, determine the least positive angle $\theta$ satisfying $(\sqrt{6})\cos \frac{1}{2}\theta + (\sqrt{10})\sin \frac{1}{2}\theta = 3$.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Derive or infer $R=4$.

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI