a. Express 5 sin 2 3 cos 2 + 6 sin cos

a. Express 5 sin² θ − 3 cos² θ + 6 sin θ cos θ in the form a sin 2θ + b cos 2θ + c, where a, b and c are constants to be found.

b. Hence find the maximum and minimum values of 5 sin² θ − 3 cos² θ + 6 sin θ cos θ.

c. Solve 5 sin² θ − 3 cos² θ + 6 sin θ cos θ = −1 for 0 < θ, 180°, rounding your answers to 1 decimal place.