Solving the Pole and Residue at a for f

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The discussion focuses on determining the nature of the function f(z) = g(z)/h(z) where g and h are analytic in a specified domain, with g(a) ≠ 0 and h(a) = 0, h'(a) ≠ 0. It is established that f has a pole at z = a and the residue can be calculated using the relationship between g and h. The user initially struggled with Laurent and Taylor expansions but clarified that Taylor expansions can be utilized under certain conditions, specifically when negative coefficients are zero, thus simplifying the analysis.

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latentcorpse
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Im getting really bugged by this question:

Let g and h be analytic in the open disc \{z \in \mathbb{C} : |z-a| < r \}, r>0and let f(z)=\frac{g(z)}{h(z)}

if g(a) \neq 0, h(a)=0, h'(a) \neq 0 show that f has a pole at z=a and find the corresponding residue of f at a.


Now I initially though we had to Laurent expand the functions g and h but that got really complicated very quickly and i couldn't find anyway of sorting stuff out.
then i tried taylor expanding them which was nicer but still didn't rearrange well.

so my 2 questions are:
(i) how do i do the above problem, and
(ii) am i correct in saying that you can't taylor expand a complex function you can only laurent expand it and if the negative coefficients turn out to be 0 then it reduces to a taylor expansion or are we allowed to do taylor expansions? if we are allowed to, aren't we ignoring the negative terms - is this allowed?
 
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Try proving first h(z)=zq(z) for some analytic q s.t. q(a) neq 0. [Here q(a)=??]
 
q(a)=g(a)/(a f(a))? why are we doing this though?
 

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