I'm just having some trouble understanding a derivation in my notes. How did it go from that first line to the second?
\begin{align*} h_n&=\frac{Kj}{2r\sin(\omega_0)}\left(-(re^{j\omega_0})^{n+1}u_{n+1}+(re^{-j\omega_0})^{n+1}u_{n+1}\right) \\ &\overset{\text{how?}}{=}\begin{cases} \frac{r^nKj}{2\sin(\omega_0))}\left(e^{-j(n+1)\omega_0}-e^{j(n+1)\omega_0}\right),\quad&n\ge-1\\ 0,&n<-1 \end{cases} \end{align*}
I understand that a rule of exponents was used $a^x ⋅ b^x = (a ⋅ b)^x$ but wouldn't that mean the $r$ in the front of the second equation should also be to the power of $n+1$ and not just $n?$ Is there a mistake somewhere?