See, if you took the derivative of this with respect to x you will get 2xy and this guy will go away x because there is no x in it.

如果你对它关于x求导,就会得到2xy，而这项就没有了,因为它里面没有。

youdao

See, if you took the derivative of this with respect to x you will get 2xy and this guy will go away x because there is no x in it.

如果你对它关于x求导,就会得到2xy，而这项就没有了,因为它里面没有。

youdao