Finding the residue of e^(-1/z^2) at z=0

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SUMMARY

The residue of the function e^{-\frac{1}{z^2}} at z=0 is confirmed to be 0. This conclusion is reached by deriving the Laurent series from the Taylor series expansion of e^z around z=0, substituting -1/z^2 into the series. The resulting series is 1 - \frac{1}{z^2} + \frac{1}{2z^4} + ..., which contains no terms of the form \frac{1}{z} that would contribute to a non-zero residue. Concerns regarding the validity of this approach are addressed, affirming that the derived series is acceptable despite originating from the Taylor series.

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latentcorpse
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This may be because I am tired but i can't find the residue of

e^{-\frac{1}{z^2}} at z=0

help!
 
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You know the Taylor's series for ez about z= 0 don't you? Replace z in that by -1/z2 to get a Laurent series for this function.
 


hmmmm

e^{-\frac{1}{z^2}}=1-\frac{1}{z^2}+\frac{1}{2z^4}+...

so the residue is 0?

i was going to do this but i got confused - why is this an acceptable form of the laurent series - we derived it from the taylor series which doesn't admit negative n values. so surely there could be some other terms that we're not taking into account?
 

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