Verify, for −180≤θ<180∘-180 \leq \theta < 180^\circ−180≤θ<180∘, that the solutions of
2sin2θ=tanθ 2 \sin 2\theta = \tan \theta 2sin2θ=tanθare θ=0,−180∘,±60∘,±120∘\theta = 0, -180^\circ, \pm 60^\circ, \pm 120^\circθ=0,−180∘,±60∘,±120∘.
348 exam-style questions on Edexcel A Level Maths Trigonometry and Modelling, covering 7.1 Addition Formulae, 7.2 Double Angle Formulae, 7.3 Solving Trigonometric Equations, 7.4 Simplifying a cos x +- b sin x, 7.5 Proving Trigonometric Identities, and 7.6 Modelling with Trigonometric Functions. Each one has a worked solution and a mark scheme showing where the marks go.