Contour Integration: Dealing With Poles

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In summary, Poles are points on a complex plane where a function is undefined or has a singularity, and they play an important role in contour integration. To identify poles, one can find the roots of the function's denominator. There are various techniques for dealing with poles in contour integration, such as using the residue theorem and partial fraction decomposition. Poles can affect the convergence of a contour integral, but their location in relation to the contour is crucial. Real-world applications of contour integration with poles can be found in physics, engineering, and medical imaging.
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pivoxa15
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If you have poles on the contour, what do you do about them?
 
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Why wouldn't you be completely free to make a new contour that goes around the old one and cuts around the point(s).

Maybe I am missing something about the question ;x
 
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pivoxa15 said:
If you have poles on the contour, what do you do about them?

The contour integral is not defined if you have poles on the contour itself. But if you are trying to compute some real integral chose a contour which avoids this.
 

FAQ: Contour Integration: Dealing With Poles

What exactly are poles in contour integration?

Poles are points on a complex plane where a function is undefined or has a singularity, meaning it cannot be continuously defined at that point. In contour integration, poles are important because they can influence the behavior of a function and change the value of the integral.

How do you identify poles in a function?

To identify poles, you first need to find the roots of the function's denominator. These roots correspond to the points on the complex plane where the function is undefined. If the function has a root of multiplicity n, it will have a pole of order n at that point.

How do you deal with poles in contour integration?

There are a few techniques for dealing with poles in contour integration. One method is to use the residue theorem, which states that the value of a contour integral around a closed path is equal to the sum of the residues of the poles inside the contour. Another method is to use a partial fraction decomposition to rewrite the function and then integrate each term separately.

Can poles affect the convergence of a contour integral?

Yes, poles can affect the convergence of a contour integral. If the contour passes through a pole, the integral may not converge at that point. However, if the pole is outside of the contour, it will not affect the convergence of the integral.

Are there any real-world applications of contour integration dealing with poles?

Yes, contour integration with poles has many applications in physics and engineering. For example, it is used in the calculation of electric and magnetic fields in electromagnetic theory, as well as in the analysis of fluid flow in aerodynamics and hydrodynamics. It is also used in signal processing and image reconstruction in medical imaging.

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