4. Sketch two pairs of curves in the ry-plane where the area between between the two curves is most easily found by integrating with respect to (a) r and (b) with respect to y. (a) (b)2. For each of the following, sketch the given curves and indicate the region bounded by them. Then set up and evaluate an integral representing the area of the region. (a) y = r and y = 12 - 2. (b) y = sin(x) and y = cos(I) for :