∫(xy^2+y-1)dx=x^2y^2/2+xy-x+c1(y)∫(x^2y+x+2)dy=x^2y^2/2+xy+2y+c2(x)x^2y^2/2+xy-x+c1(y)=x^2y^2/2+xy+2y+c2(x)c1(y)=2y+c，c2(x)=-x+c原函数 f(x，y)=x^2y^2/2+xy-x+2y+c
