6. 5. Set up and evaluate a double integral representing the volume under the surface z = x + y but above the region in the first quadrant of the x, y -plane outside of the circle r = 4 and inside the petal of the rose r = 8sin (90) which is closest to the positive x-axis. Evaluate a double integral to compute the mass of the lamina occupying the same region in the x, y -plane as in problem #2, where the density in mg/cm at any point (x, y) is the reciprocal of the distance from the pole (0,0). Then set up but do NOT evaluate integrals for the coordinates of the center of mass.