1>=y>=0,0<=y<=x²<=2-y²<=2,得0<=x<=√2,
根据图像,需要把x分为2段(0,1)和(1,√2)
原式=∫[0->1] dx∫[0->x²] f(x,y)dy + ∫[1->√2] dx∫[0->√(2-x²)] f(x,y)dy