Solve, for −180≤x≤180-180 \leq x \leq 180−180≤x≤180, the equation,
2cos2x+7cosx=0 2 \cos 2x + 7 \cos x = 0 2cos2x+7cosx=0Practise Edexcel A Level Maths 7.2 Double Angle Formulae with exam-style questions for A Level Maths. 24 questions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.