W^3
Posts:
28
Registered:
4/19/11
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Re: Elementary complex analysis
Posted:
Mar 8, 2013 4:00 PM
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Another proof: Let f(z) = sum(n=0,oo) a_nz^n. Then f(1/z) = sum(n=0,oo) a_n/z^n. Now f(1/z) -> oo as z -> 0. Hence by Casatori-Weierstrass, f(1/z) has a pole at 0. Thus f(1/z) = sum(n=0,N) a_n/z^n => f(z) = sum(n=0,N) a_nz^n.
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