第2个回答 2020-04-28
∫∫∫<Ω>xdxdydz = ∫<0, 1>dz∫<0, 1-z>dy∫<0, (1-y-z)/2>xdx
= (1/2)∫<0, 1>dz∫<0, 1-z>dy[x^2]<0, (1-y-z)/2>
= (1/8)∫<0, 1>dz∫<0, 1-z>(1-y-z)^2dy
= (-1/24)∫<0, 1>dz[(1-y-z)^3]<0, 1-z>
= (1/24)∫<0, 1>(1-z)^4dz
= (-1/120)[(1-z)^5]<0, 1> = 1/120