For sinθ≠0\sin \theta \neq 0sinθ=0 and cosθ≠0\cos \theta \neq 0cosθ=0, prove that
cosec 2θ−cot2θ=tanθ \text{cosec } 2\theta - \cot 2\theta = \tan \theta cosec 2θ−cot2θ=tanθExplain why the identity cosec 2θ−cot2θ=tanθ\text{cosec } 2\theta - \cot 2\theta = \tan \thetacosec 2θ−cot2θ=tanθ is not valid when sinθ=0\sin \theta = 0sinθ=0.
38 exam-style questions on AQA A Level Maths 1.8.8 Proofs with trigonometric identities. Each one has a worked solution and a mark scheme showing where the marks go.