Solve, for −180≤x≤180-180 \leq x \leq 180−180≤x≤180, the equation,
cos2x−7sinx+3=0 \cos 2x - 7 \sin x + 3 = 0 cos2x−7sinx+3=0137 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.