Chapter 7.13, Problem 8MP

From facts you know, find in your head the average value of

(a) $x^3-3\sinh 2x+{\sin }^2\pi x+\cos 3\pi x$ on $(-5,5)$.

(b) $2{\sin }^{2}3x-4\cos x+5x\cosh 2x-x{\cos }^{2}x$ on $(-\pi ,\pi ).$