Edexcel GCE Core Mathematics C3 January 2011 exam answers review

1. Express 7cosx − 24sin x in the form R cos (x + α) where R>0 and 0<α<π/2 . Give the value of α to 3 decimal places.

   (3)

2. Hence write down the minimum value of 7cosx – 24sinx.(1)

3. Solve, for 0≤x<2π, the equation

   7 cos x − 24sin x =10

   giving your answers to 2 decimal places.

   (5)

Express