(a)[3]
Show that the equation $\cot^2 \theta + 2\cos 2\theta = 4$ can be transformed into the form $4\sin^4 \theta + 3\sin^2 \theta - 1 = 0$.
(b)[3]
Hence solve the equation $\cot^2 \theta + 2\cos 2\theta = 4$, for $0^\circ < \theta < 360^\circ$.
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: “Apply trigonometric identities to express the equation in terms of $\sin\theta$.” …
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