sin(x^2+y^2)=x
两边同时求导,得
(x^2+y^2)'cos(x^2+y^2)=dx
(2xdx+2ydy)cos(x^2+y^2)=dx
2xdx+2ydy=dx/cos(x^2+y^2)
2ydy=dx/cos(x^2+y^2)-2xdx
dy=(dx/cos(x^2+y^2)-2xdx)/2y