计算三重积分∫∫∫(x⼀a+y⼀b+z⼀c)dV 积分域为三个坐标面和平面x⼀a+y⼀b+z⼀c=1(a,b,c>0)所围成的区域

2025-05-17 02:29:56
推荐回答(1个)
回答1:

∫∫∫1dxdydz
=∫[0→a]dx∫[0→b-bx/a]dy∫[0→c-x/a-y/b]
1
dz
=∫[0→a]dx∫[0→b-bx/a]
(c-cx/a-cy/b)
dy
=c∫[0→a]
(y-xy/a-y²/(2b))
|[0→b-bx/a]
dx
=bc∫[0→a]
[(1-x/a)
-
(x/a-x²/a²)
-
(1-x/a)²/2]
dx
=abc[-(1-x/a)²/2
-
(x²/(2a²)
-
x³/(3a³))
-
(1-x/a)³/6]
|[0→a]
=abc/6
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