Analytic Function with a Pole at 1

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SUMMARY

The discussion centers on proving properties of an analytic function \( f \) that has a pole at \( z = 1 \) within the disc \( (0, r) \) where \( r > 1 \). It establishes that there exists a positive integer \( N \) such that the coefficients \( a(k) \) of the power series expansion of \( f \) are non-zero for all \( k \geq N \). Additionally, it concludes that the limit \( \lim (a(N+j+i)/a(N+1)) = 1 \) holds true, indicating a specific behavior of the coefficients as \( k \) increases.

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Homework Statement



Let r>1, let f be analytic in the disc (0,r)\{1}, and suppose that f has apole at 1.

Let sum(a(k) *z(k)) be the power series expansion of f in the disc (0,r). Prove that there is a positive integer N so that a(k) not equal to zero for k>= N, and that

lim (a(N+j+i)/a(N+1))=1


Homework Equations





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