∫∫∫<Ω>z^2dxdydz=∫<0,c>z^2dz∫<0,b(1-z/c)>dy∫<0,a(1-z/c-y/b)>dx=∫<0,c>z^2dz∫<0,b(1-z/c)>a(1-z/c-y/b)dy=a∫<0,c>z^2[b(1-z/c)^2-b(1-z/c)^2/2]dz=(ab/2)]∫<0,c>[z^2-2z^3/c+z^4/c^2)dz=(ab/2)c^3(1/3-1/2+1/5)=abc^3/60,可以吗?