I'm trying to figure out $z^{p/q}$ where $p,q$ are coprime.
Suppose I want to find $z^{2/7}$ where $z=128$. I can rewrite $z=128e^{0}$
Now I know that the $z^{1/7}$ roots are $2e^{k2\pi i/7}$ for $k=0,...6$.
What if now I need to compute the power $2/7$? Is it simply $2e^{4k\pi i/7}$.