2. 15.6, Triple Integrals in Rectangular Coordinates: (a) Sketch the region bounded by the surfaces z = x* + y , x = 0, y = 0, z = 0, x+y =1. Each pair of the surfaces intersects in a curve. Be sure to include these curves in your sketch. Then use a triple integral to calculate the volume of the solid. (b) Find the volume of the region in the first octant bounded by the coordinate planes, the plane x + z = 2, and the parabolic cylinder y = 9 - x2