Laurent series for this function

Carl140
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Homework Statement



Find the Laurent series of the function f(z) = Sin(1/(z^2-z)) in the region 0<|z|<infinity.


The Attempt at a Solution



Now sin(z) = [e^(iz) - e^(-iz)]/(2i)

Shall we replace z by 1/(z^2-z) to obtain the Laurent series for f(z)?
I tried this but it gets messy. Is there a clever method? or any other approach?
 
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I would try using the series expansion
\sin(z) = z - \frac{z^3}{3!} + \frac{z^5}{5!} - \cdots
without going through the exponentials. That should be cleaner, but I haven't checked and I don't know if it's the best way to go.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...

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