5.6 Let R be the solid torus in ' obtained by revolving the circle (y - a) + z b', in the yz-plane, about the z-axis. Note that the mapping T: 3 - ' defined by x = (a + w cos v)cos #, y = (a + w cos v)sin u, z = w sin v, maps the interval Q - {(w, v, w) : w, ve [0, 2wr] and we [0, b]] onto this torus. Apply the change of variables formula to calculate its volume