Dear all, I evaluate a multiple integral (need to do 6 times). Maple cannot find analytical solution, so i try numerical as follows. But it still dind't give me a solution. Why? Is it because the function is too complex and too many integral? Thanks a lot! R := 250; l := 1500; e := 2000; n := 5; a := 100; alpha := 2000; beta := 2000; h := (x,y,s,t,u,v)->(1/(pi*n*(a^2)))^3 * exp(-(1/(n*(a^2))*((x-alpha)^2+(y-beta)^2+(s-x)^2+(t-y)^2+(u-s)^2+(v-t)^2))); Int(Int(Int(Int(Int(Int(h(x,y,s,t,u,v),x=0..2*R),y=0..l),s=e..2*R+e),t=0..l),u=2*e..2*R+2*e),v=0..l); evalf(%);