How to prove $D_x^k(x^k)=k!$?
Well, I know first I have to prove $D_x^1(x^1)=1!$ which is easy to prove, then I will prove
Assume $$D_x^k(x^k)=k!$$
Show: $$D_x^{k+1}(x^{k+1})=(k+1)!$$
Which I stuck on it.
$$ \begin{align} D_x^{k+1} x^{k+1} &= D_x^k D_x^1 x^{k+1} \\ &= (k+1) D_x^k x^k \end{align} $$
I think you got the rest
Copyright © 2021 JogjaFile Inc.
$$ \begin{align} D_x^{k+1} x^{k+1} &= D_x^k D_x^1 x^{k+1} \\ &= (k+1) D_x^k x^k \end{align} $$
I think you got the rest