Please anwer all 3 questions

(8) (6 points) Let r E [-1, 1]. Verify that 1-12 Vi -12 - y? dy = = . (1-12). Hint: To avoid getting undefined expressions when evaluating this integral, use that V1 -12 - y2 dy = lim V1 -x2 - y2 dy (left-sided limit). t-V1-12 (9) (4 points) Show that the volume of the unit sphere {(x, y, z) ( R3 : 12 + y? + 22