Evaluate and find the principal value of $(-1+i)^ {2-i}$ Can anyone please help me evaluate and find the principal value of
$(-1+i)^{2-i}$
I got up to 
$=e^{2-i}(ln(-1+i))$
$=e^{(2-i)(1/2 ln(2)+i(3pi/4))}$

\begin{align}
(-1+i)^{2-i} &= \left[ e^{\pi i} \, \sqrt{2} \, e^{- \pi i/4} \right]^{2 - i} \\
&= e^{2 \pi i + \pi} \, e^{(2-i) \ln(\sqrt{2})} \, e^{- \pi i/2 - \pi/4} \\
&= 2 \, e^{ 3 \pi/4} \left( e^{i(3 \pi + \ln(2))/2} \right)\\
&= 2 \, e^{ 3 \pi/4} \left[ \cos\left( \frac{3 \pi + \ln(2)}{2} \right) + i \, 
\sin\left( \frac{3 \pi + \ln(2)}{2} \right) \right]  
\end{align}
The principle value is
\begin{align}
2 \, e^{ 3 \pi/4} \, \cos\left( \frac{3 \pi + \ln(2)}{2} \right)
\end{align}
and the argument is
\begin{align}
2 \, e^{ 3 \pi/4} \, \sin\left( \frac{3 \pi + \ln(2)}{2} \right)
\end{align}
