What I showed you at the beginning, and then erased, basically justifies how to take the derivative of a reciprocal function.

最开始我讲过了，如何对倒数函数求导。

youdao

What I showed you at the beginning, and then erased, basically justifies how to take the derivative of a reciprocal function.

最开始我讲过了，如何对倒数函数求导。

youdao