
10.8.2 Series with complex terms
Problem:
Find all expansions of the given function \( f(z) \) in powers of \( z-a \) and indicate the domains of these expansions.
Remark 1. For a multivalued function \( \sqrt[3]{z} \mathrm{p} \) we consider the branch, which that takes real values on the positive part of the real axis.
Remark 2. For the multivalued function \( \arctan z \) we consider the branch that takes real values on the positive part of the real axis. In this case, there is a representation:
\[
\begin{array}{l}
\arctan z=\int_{0}^{z} \frac{d z}{1+z^{2}}=\frac{\pi}{2}+\int_{\infty}^{z} \frac{d z}{1+z^{2}} \\
f(z)=\frac{z-1}{\sqrt[3]{z^{3}-3 z^{2}+3 z}} \text { in powers of }(z-1) .
\end{array}
\]