Suppose that m and n are integers. compute r 2π 0 cos(mx) cos(nx) dx. (be careful: there will be two different results, one when m = n and one when m 6= n.) (b) explain why the result you got for the m 6= n case is not valid when m = n. (c) suppose f(x) = a cos(x) + b cos(2x) + c cos(3x), and that you also know r 2π 0 f(x) cos(x) dx = 5 ; r 2π 0 f(x) cos(2x) dx = 6 ; r 2π 0 f(x) cos(3x) dx = 7 . find a and b and