- #1
Amad27
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Homework Statement
Homework Equations
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The Attempt at a Solution
As you see in the solution, I am confused as to why the sum of residues is required.
My question is the sum:
$$(4)\cdot\sum_{n=1}^{\infty} \frac{\coth(\pi n)}{n^3}$$
Question #1:
-Why is the beginning n=1 the residue is for all $$n \in (-\infty, \infty)$$ so the beginning of the sum should be $$n=-\infty$$ right?
Question #2:
Also in the residue theorem, it states:
$$\oint_{C} f(z) dz = (2\pi i)(\sum \text{Res})$$
Where is the 2pi(i) gone in the solution of theirs?
Thanks!