(a)[3]
Prove the identity $\dfrac{\sin^2 x - \cos x - 1}{1 + \cos x} = -\cos x$.
(b)[3]
Hence solve the equation $\dfrac{\sin^2 x - \cos x - 1}{2 + 2\cos x} = \dfrac{1}{4}$ for $0^\circ \leq x \leq 360^\circ$.
Mathematics 9709 · AS & A Level · Trigonometry
Trigonometry — practice question
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Applies the identity $\sin^2x+\cos^2x=1$ in order to simplify” …
- Full mark scheme, point by point
- Step-by-step worked solution
- Write your answer & get it marked instantly by AI