dy/dx = (xy)/(x²+y²)的通解

问题描述:

dy/dx = (xy)/(x²+y²)的通解

dx/dy=x/y+y/x
x=py
x'=p'y+p
p'y+p=p+1/p
pp'=1/y
两边积分得
1/2p^2=lny+Cp是什么啊?晕,x=py啊