Can the Residue Theorem be applied to these contour integrals?

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SUMMARY

The discussion centers on the application of the Residue Theorem to the contour integral $$\int_C \frac{1+z}{(z-1)(z^2+9)}\,dz$$ across three specified cases of contour radii: |z| = 2, |z+1| = 1, and |z-i| = 3. It is confirmed that each case allows for a straightforward application of the Residue Theorem. Additionally, it is clarified that poles must be strictly inside the contour for the theorem to apply; poles on the boundary require special treatment.

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itsnogood
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Hi, first post here. I'm having some trouble with contour integration. Basically here's the question:

Contour Integral of

1+z dz
(z-1)(z2+9)

There are three cases:

l z l = 2
l z+1 l = 1
l z-\iota l = 3

Is each case a straightforward application of the residue theorem? Also, reading up in my textbook the poles should be contained within the contour so does on the boundary count?

Thanks in advance.
 
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itsnogood said:
Hi, first post here. I'm having some trouble with contour integration. Basically here's the question:

Contour Integral of

1+z dz
(z-1)(z2+9)
You should take a little time and learn LaTeX. It's not very difficult.
$$\int_C \frac{1+z}{(z-1)(z^2+9)}\,dz$$
There's a good tutorial here: https://www.physicsforums.com/showthread.php?p=3977517#post3977517

There are three cases:

l z l = 2
l z+1 l = 1
l z-\iota l = 3

Is each case a straightforward application of the residue theorem?
Yup.

Also, reading up in my textbook the poles should be contained within the contour so does on the boundary count?
No, the pole needs to be inside the contour. If it's on the contour, you have to treat it differently.
 

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