3. Let f(x) be a 2x-periodic function with Fourier series given by F(x) = 2+) (-4)* (2k)! cos(kx) +> sin(kx) *=1 k=1 Simplify your answers to following as much as possible. (a) (4 points) Find the average value of f (x) over [-7, "]. (b) (4 points) Find f(x) cos (3x) dr. (c) (5 points) Find (4f (x) sin(3x) - 5cos(2x)) da. (d) (6 points) Find F(2 )