Int(Int(x^4-y^2,x=1..2),y=0..1) = int(int(x^4-y^2,x=1..2),y=0..1); Int(Int(sin(x+y),x=0..Pi/2),y=0..Pi/2)= Int(int(sin(x+y),x=0..Pi/2),y=0..Pi/2); Int(int(sin(x+y),x=0..Pi/2),y=0..Pi/2) = int(int(sin(x+y),x=0..Pi/2),y=0..Pi/2); z := 1 - (x^2/4 + y^2/9); plot3d(z,x=-1..1,y=-2..2,axes=frame); Int(Int(z,x=-1..1),y=-2..2) = int(int(z,x=-1..1),y=-2..2); ans1 := evalf(int(int(z,x=-1..1),y=-2..2),2); z2 := x*sqrt(x^2+y); with(mvcal): blockapp(z2,x=0..1,y=0..1); plot3d(z2,x=-1..2,y=-1..2,axes=frame); Int(Int(z2,x=0..1),y=0..1); evalf("); ans2 := int((1+y)^(3/2)-y^(3/2),y=0..1)/3; evalf(");