In a study of harmonic oscillators, a phase angle ϕ\phiϕ is found to satisfy the equation
4cosecϕ=9cosϕ 4 \operatorname{cosec} \phi = 9 \cos \phi 4cosecϕ=9cosϕfor 0<ϕ<π0 < \phi < \pi0<ϕ<π. Determine the possible values of ϕ\phiϕ, in radians, giving your answers to 3 significant figures.
The configuration of a robotic linkage is governed by the equation
tan3θ−tan20∘1+tan3θtan20∘=2 \frac{\tan 3\theta - \tan 20^\circ}{1 + \tan 3\theta \tan 20^\circ} = 2 1+tan3θtan20∘tan3θ−tan20∘=2for 0∘<θ<180∘0^\circ < \theta < 180^\circ0∘<θ<180∘. Solve this equation to find the possible orientations θ\thetaθ, giving your answers to one decimal place.
317 exam-style questions on OCR A Level Maths 1.5 Trigonometry, covering 1.5.1 Definitions for all arguments, 1.5.2 Sine and cosine rules, 1.5.3 Area of a triangle, 1.5.4 Radian measure (A-level only), 1.5.5 Small angle approximations (A-level only), 1.5.6 Graphs of basic trigonometric functions, 1.5.7 Exact values in radians (A-level only), 1.5.8 Reciprocal and inverse trigonometric ratios (A-level only), 1.5.9 Graphs of reciprocal and inverse functions (A-level only), 1.5.10 Trigonometric identities, 1.5.11 Further trigonometric identities (A-level only), 1.5.12 Double angle and compound angle formulae (A-level only), 1.5.13 Geometrical proofs of formulae (A-level only), 1.5.14 Harmonic form Rcos / Rsin (A-level only), 1.5.15 Trigonometric equations, 1.5.16 Proof involving trigonometric functions (A-level only), and 1.5.17 Trigonometric functions in context. Each one has a worked solution and a mark scheme showing where the marks go.