Integral could lead to Hypergeometric function

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Discussion Overview

The discussion revolves around the evaluation of a specific integral involving parameters that are all positive and a variable exponent n. Participants explore the conditions under which the integral converges and its relation to the hypergeometric function when certain parameters are set to zero.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant presents an integral and notes that setting the parameter b to zero leads to a hypergeometric function.
  • Another participant questions the convergence of the integral, suggesting it may converge for some values of n, which could be either positive or negative.
  • A later reply reiterates the convergence discussion, indicating that the integral is not convergent for any integer values of n, including positive, negative, or zero.
  • One participant proposes a potential simplification of the integral using partial fractions but expresses uncertainty about the approach.
  • There is a request for clarification regarding the conditions under which n can be considered, highlighting a need for a non-contradictory phrasing of the question about the sign of n.

Areas of Agreement / Disagreement

Participants express differing views on the convergence of the integral, with some suggesting it converges for certain values of n while others assert it does not converge for any integer values of n. The discussion remains unresolved regarding the specific conditions for convergence.

Contextual Notes

Participants note that the integral's convergence is dependent on the values of n, and there are unresolved assumptions regarding the parameters and their effects on convergence.

DMESONS
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How can I perform this integral



\begin{equation}
\int^∞_a dq \frac{1}{(q+b)} (q^2-a^2)^n (q-c)^n ?
\end{equation}

all parameters are positive (a, b, and c) and n>0.

I tried using Mathemtica..but it doesn't work!

if we set b to zero, above integral leads to the hypergeometric function!
 
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Hi !

What do you think about the convergence, or not ?
 
JJacquelin said:
Hi !

What do you think about the convergence, or not ?

Thanks for your comment.

The integral is convergent for some values of (n) which can be either positive or negative.

As I mentioned, if I set b =0, the result have the form of hypergeometric function!

But if b is not zero, Mathematica can't solve it.
 
DMESONS said:
How can I perform this integral



\begin{equation}
\int^∞_a dq \frac{1}{(q+b)} (q^2-a^2)^n (q-c)^n ?
\end{equation}

all parameters are positive (a, b, and c) and n>0.

I tried using Mathemtica..but it doesn't work!

if we set b to zero, above integral leads to the hypergeometric function!
I'll preface this by asking what it is for, but I'll try to provide a partial solution, too.

To start, what on Earth is this for? We do we come up with such silly things to integrate?

Second, let's see if we can simplify things considerably:

$$\int\limits_{[a,+\infty)}\left(\frac{1}{q+b}(q^2-a^2)^n(q-c)^n\right)\mathrm{d}q=\int\limits_{[a,+\infty)}\left(\frac{1}{q+b}(q-a)^n(q+a)^n(q-c)^n\right)\mathrm{d}q.$$

I'm thinking we might just approach this by means of partial fractions. On cursory examination, I don't see a contour that would simplify things, so brute force might be necessary.
 
DMESONS said:
all parameters are positive (a, b, and c) and n>0.
DMESONS said:
The integral is convergent for some values of (n) which can be either positive or negative.
Hi !
Would you mind give a non contradictory wording of the question about the sign of n.
 
DMESONS said:
The integral is convergent for some values of (n) which can be either positive or negative.

Hi !
For which value of (n) the integral is convergent ?
Clue : The integral is NOT convergent for any integer (n), either positive or negative or n=0.
 

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