Verify that, for 0≤θ<2π0 \leq \theta < 2\pi0≤θ<2π, the solutions of
cos(θ+π3)=sinθ \cos\left(\theta + \frac{\pi}{3}\right) = \sin \theta cos(θ+3π)=sinθare θ=π12\displaystyle \theta = \frac{\pi}{12}θ=12π and θ=13π12\displaystyle \theta = \frac{13\pi}{12}θ=1213π.
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.