For sinθ≠0\sin \theta \neq 0sinθ=0, prove that
cosec 2θ−cot2θ=tanθ\text{cosec } 2\theta - \cot 2\theta = \tan \thetacosec 2θ−cot2θ=tanθ
Explain 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.
Practise Edexcel A Level Maths Trigonometry and Modelling with exam-style questions for A Level Maths. 100 questions covering 7.1 Addition Formulae, 7.2 Double Angle Formulae, 7.3 Solving Trigonometric Equations, 7.4 Simplifying a cos x +- b sin x, 7.5 Proving Trigonometric Identities, and 7.6 Modelling with Trigonometric Functions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.