Example 4.32. Assume D is a disk of radius 2 centered at 0 and let f(x, y) = 1 - 12 - y. Compute JJ f. Hint: J cos (ax) dx = 5x + 1 sin(2ax) and f sin?(ar) cos (ar)de = 1 - 27 sin(4ax). D = { (x, y) 1 202 + 32