The problem is I just can't multiply let's say the first by itself without knowing for sure if the result is a convergent series... I was told it had to do with the Binomial Series Theorem:
http://en.wikipedia.org/wiki/Binomial_theorem
And with that I got the 3rd and 4th in the first ring (but...
Yeah, I'm sorry, I'm asked to find the laurent series of
f(z) = \frac{1}{(2-z)^2(1-z)^2}
in two rings: 1<|z|<2 and |z|>2. Using partial fractions I got
f(z) = \frac{-2}{1-z} + \frac{1}{(1-z)^2} + \frac{2}{2-z} + \frac{1}{(2-z)^2}
and I can easily obtain the laurent series in both rings...
Homework Statement
I'm asked to find the Laurent series of some rational function and using partial fractions I encounter something like 1/(c-z)^2 with c > 0.
Homework Equations
The Attempt at a Solution
I've tried several 'algebraic tricks' like multiplying for z^2 or just...