R1 := Int(Int(f(x,y),y=g1(x)..g2(x)),x=a..b); R2 := Int(Int(f(x,y),x=f1(y)..f2(y)),y=c..d); f := (x,y) -> x^3*y^2+x*y: 'f(x,y)' = f(x,y); h1 := x^2+x; h2 := x^3-x; inter := solve(h1-h2,x); plot({h1,h2},x=-2..2.5,axes=frame); Ans1 := Int(Int(f(x,y),y=h2..h1),x=0..2)=int(int(f(x,y),y=h2..h1),x=0..2); ans1 := evalf(304576/5005); plot({[cos(t),sin(t),t=0..Pi/2],[2*cos(t),2*sin(t),t=0..Pi/2]}, x=-3..3,y=-3..3); Ans2 := Int(Int(g(x,y),y=sqrt(1-x^2)..sqrt(4-x^2)),x=0..1) + Int(Int(g(x,y),y=0..sqrt(4-x^2)),x=1..2);