Establish the following trigonometric results:
cosec2ϕ−tan2ϕ≡cot2ϕ−sec2ϕ+2\text{cosec}^2 \phi - \tan^2 \phi \equiv \cot^2 \phi - \sec^2 \phi + 2cosec2ϕ−tan2ϕ≡cot2ϕ−sec2ϕ+2
(secx+cosx)2≡tan2x+cos2x+3(\sec x + \cos x)^2 \equiv \tan^2 x + \cos^2 x + 3(secx+cosx)2≡tan2x+cos2x+3
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.