Using the disk method, find the volumes of the following solids of revolution: 1 (a) y=z, z=0, y = 1, rotated around the z-axis; (b) y, z=2, y = 3, rotated around the z-axis; (c) y=y, y=1, rotated around the y-axis; (d) y=4-x, y, z=0, rotated around the y-axis;