Prove that:
sec4A−tan4A≡2sec2A−1\sec^4 A - \tan^4 A \equiv 2\sec^2 A - 1sec4A−tan4A≡2sec2A−1
Hence solve, for 0≤A≤3600 \leq A \leq 3600≤A≤360, the equation,
sec4A−tan4A=3 \sec^4 A - \tan^4 A = 3 sec4A−tan4A=354 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.