Given that x=30∘x=30^\circx=30∘ and x=−90∘x=-90^\circx=−90∘ are solutions of the equation,
cos2x−asinx+b=0 \cos 2x-a\sin x+b=0 cos2x−asinx+b=0find the value of a a\,a and the value of bbb.
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.