4.三维傅氏积分 f()=2d"d r=ix+1y+ kz 0=e101+e202+e303 dr-dxdyd2,do-dordo2do4. 三维傅氏积分 ( ) òòò ò ò ò ¥ -¥ ¥ -¥ - × × = w p r v w v v v w v v v f r f r e dr e d i r i r [ ( ) ] 2 1 ( ) 3 dr = dxdydz , dw = dw1dw 2 dw 3 v w 1w1 2w2 3w3 e e e v v v v = + + r i x jy kz v v v = + +