Prove the identity: 4sec2x−4cosec2x≡4tan2x−4cot2x4\sec^2x - 4\operatorname{cosec}^2x \equiv 4\tan^2x - 4\cot^2x4sec2x−4cosec2x≡4tan2x−4cot2x
Prove the identity: (secx−4cosx)2≡tan2x−16sin2x+9(\sec x - 4\cos x)^2 \equiv \tan^2 x - 16\sin^2 x + 9(secx−4cosx)2≡tan2x−16sin2x+9
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.