Use the identity cos2θ+sin2θ=1\cos^2 \theta + \sin^2 \theta = 1cos2θ+sin2θ=1 to prove that tan2θ=sec2θ−1\tan^2 \theta = \sec^2 \theta - 1tan2θ=sec2θ−1.
Solve, for 0≤θ<360∘0 \leq \theta < 360^\circ0≤θ<360∘, the equation
2tan2θ+4secθ+sec2θ=2. 2 \tan^2 \theta + 4 \sec \theta + \sec^2 \theta = 2. 2tan2θ+4secθ+sec2θ=2.Practise Edexcel A Level Old Maths Trigonometry with exam-style questions for A Level Old Maths. 13 questions, matched to the Edexcel A Level Old Maths (9371) specification and written in Unit exams C1, C2, C3 and C4 plus two applied units (e.g. S1 and M1) style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.