{ y = x²、y = 0
{ x = 1
∫∫ xy dxdy
= ∫[0→1] dx ∫[0→x²] xy dy
= ∫[0→1] x * [y²/2]：[0→x²] dx
= ∫[0→1] x/2 * x⁴ dx
= ∫[0→1] (1/2)x⁵ dx
= (1/2)(1/6)x⁶：[0→1]
= 1/12
可以说简单画个图就解决了.