Complex Analysis (Practice Exam)

PieceOfPi
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Homework Statement



This question is in my exam review problem from my complex analysis class.
Compute f(100)(0)/100!, where f(z) = 1/(1+i-sqrt(2)z).

(f(100)(0) means the 100th derivative of f evaluated at 0.)

Homework Equations



Cauchy's integral formula might be helpful.

The answer to this question is -1/(1+i).

The Attempt at a Solution



I thought about using Cauchy's integral formula, but it seems like I need to rewrite f(z) so that I have singularity at 0... or maybe I'm completely missing out.

Thanks!
 
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Have you tried writing the function as it's series representation about 0? Then the calculation you are looking for would be the coefficient in front of the z^100 term.
 
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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