Prove the identity: (secx−2cosx)2≡tan2x−4sin2x+1(\sec x - 2\cos x)^2 \equiv \tan^2 x - 4\sin^2 x + 1(secx−2cosx)2≡tan2x−4sin2x+1
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.