Someone me with this Laurent Expansion

Jonnnnn
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Homework Statement


the Laurent expansion of f(z)=e1/sin(z) at the isolated singularity z=π

Homework Equations

The Attempt at a Solution


I tried rewriting 1/sin(z) into exponential form, but it seems have no help for the expansion. Would someone give me some inspirations?
 
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Can you remove the singularity?
 
RUber said:
Can you remove the singularity?
Actually, the singularity here is an essential singularity, which is not removable I think.
 
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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