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
38 exam-style questions on AQA A Level Maths 1.8.8 Proofs with trigonometric identities. Each one has a worked solution and a mark scheme showing where the marks go.