Prove the identity
sin2x1+cot2x≡2sin3xcosx \frac{\sin 2x}{1 + \cot^2 x} \equiv 2 \sin^3 x \cos x 1+cot2xsin2x≡2sin3xcosxHence find
∫6sin4θ1+cot22θ dθ \int \frac{6 \sin 4\theta}{1 + \cot^2 2\theta} \, d\theta ∫1+cot22θ6sin4θdθ31 exam-style questions on Edexcel A Level Maths 11.3 Using Trigonometric Identities. Each one has a worked solution and a mark scheme showing where the marks go.