Prove the identities:
tan2x−cot2x≡sec2x−cosec2x\tan^2x - \cot^2x \equiv \sec^2x - \text{cosec}^2xtan2x−cot2x≡sec2x−cosec2x
tan2x−sin2x≡(secx−cosx)2\tan^2x - \sin^2x \equiv (\sec x - \cos x)^2tan2x−sin2x≡(secx−cosx)2
274 exam-style questions on Edexcel A Level Maths Trigonometric Functions, covering 6.1 Secant, Cosecant and Cotangent, 6.2 Graphs of Sec x, Cosec x and Cot x, 6.3 Using Sec x, Cosec x and Cot x, 6.4 Trigonometric Identities, and 6.5 Inverse Trigonometric Functions. Each one has a worked solution and a mark scheme showing where the marks go.