Use the identity cos2θ+sin2θ≡1\cos^2\theta + \sin^2\theta \equiv 1cos2θ+sin2θ≡1 to prove that tan2θ≡sec2θ−1\tan^2\theta \equiv \sec^2\theta - 1tan2θ≡sec2θ−1.
Solve, for 0°≤θ≤360°0° \leq \theta \leq 360°0°≤θ≤360°, the equation
tan2θ+sec2θ+5secθ=2\tan^2\theta + \sec^2\theta + 5\sec\theta = 2tan2θ+sec2θ+5secθ=2
Give your answers to one decimal place.
317 exam-style questions on AQA A Level Maths 1.8 E: Trigonometry, covering 1.8.1 Trigonometric definitions, rules and radians, 1.8.2 Small angle approximations (A-level only), 1.8.3 Trigonometric functions and exact values, 1.8.4 Reciprocal and inverse trigonometric functions (A-level only), 1.8.5 Trigonometric identities, 1.8.6 Compound and double angle formulae (A-level only), 1.8.7 Solving trigonometric equations, 1.8.8 Proofs with trigonometric identities, and 1.8.9 Trigonometry in context. Each one has a worked solution and a mark scheme showing where the marks go.