=∫cx2+y2)d-p2 d小y =∫ rrdrdedz-∫y2tcd 0≤r≤1 0≤6≤ j2 dedrdrl2 dz-J2sin20doordr 元 48 K心  = (x + y )dv 2 2   − 3 2 y zdxdy . 48  = −   = r rdrddz 2 =    1 1 0 3 2 0 2 r d r dr dz        − 2 0 0 1 2   r y dxdy −   1 0 3 2 0 2 sin d r dr   