$$\frac{d(u^{n})}{du}=nu^{n-1}$$
$n\in \mathrm{C}$
$u\in \mathrm{C}$
$\left\{\begin{matrix}\\u>0\text{, }&\text{unconditionally}\\u<0\text{, }&Denominator(n)\text{bmod}2=1\\u=0\text{, }&n>1\end{matrix}\right.$
