Is it Possible to show this? Beta function

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Discussion Overview

The discussion revolves around demonstrating the equivalence of two versions of a particular function using properties of Beta functions and the Gaussian hypergeometric function. Participants explore mathematical approaches to establish this equivalence, focusing on integrals and series representations.

Discussion Character

  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant presents an integral involving the Beta function and proposes a method to show the equivalence of two function versions through this integral.
  • The integral is expressed as a series involving the Beta function, leading to a proposed equality that connects the two versions of the function.
  • Conditions for the validity of the proposed equality are specified, including restrictions on the real parts of certain parameters.
  • Another participant acknowledges the first participant's contributions and offers assistance regarding forum functionalities, indicating a supportive community environment.

Areas of Agreement / Disagreement

The discussion does not appear to have reached a consensus on the equivalence of the two function versions, as it primarily consists of one participant's exploration of the problem and another's supportive comments.

Contextual Notes

Participants mention specific conditions under which the mathematical expressions hold, highlighting the importance of these conditions in the context of the discussion.

chamilka
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Hi everyone!
I got two versions of one particular function and now I need to show those two versions are equivalent.
For that I need to show the follwing, View attachment 223

Is it possible to show this by using the properties of Beta functions, Gaussian hypergeometric function etc?

Thanks in advance!
 

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chamilka said:
Hi everyone!
I got two versions of one particular function and now I need to show those two versions are equivalent.
For that I need to show the follwing, View attachment 223

Is it possible to show this by using the properties of Beta functions, Gaussian hypergeometric function etc?

Thanks in advance!

Hi chamilka, :)

I got the intuition of solving this problem from your http://www.mathhelpboards.com/threads/1358-Chamilka-s-Question-from-Math-Help-Forum. Consider the integral, \(\displaystyle\int_{0}^{1}x^{y+\alpha-1}(1-x)^{(n+\beta-y)-1}\,dx\).

\begin{eqnarray}

\int_{0}^{1}x^{y+\alpha-1}(1-x)^{(n+\beta-y)-1}\,dx&=&\int_{0}^{1}x^{y+\alpha-1}(1-x)^{n-y}(1-x)^{\beta-1}\,dx\\

&=&\int_{0}^{1}x^{y+\alpha-1}(1-x)^{n-y}\sum_{i=0}^{\infty} \; {\beta-1\choose i}\;(-x)^{i}\,dx

\end{eqnarray}

Proceed with the same method I have gone through in http://www.mathhelpboards.com/threads/1358-Chamilka-s-Question-from-Math-Help-Forum?p=6487&viewfull=1#post6487, and you will finally get,

\[\int_{0}^{1}x^{y+\alpha-1}(1-x)^{(n+\beta-y)-1}\,dx=\sum_{i=0}^{\infty}(-1)^{i}{\beta-1\choose i}B(y+\alpha+i,\,n-y+1)~~~~~~~~~~~(1)\]

provided, \(Re(y+\alpha+i)>0\mbox{ and }Re(n-y+1)>0\).

Also by the definition of the Beta function, if \(Re(y+\alpha)>0\mbox{ and }Re(n+\beta-y)>0\) we have,

\[\int_{0}^{1}x^{y+\alpha-1}(1-x)^{(n+\beta-y)-1}\,dx=B(y+\alpha,\,n+\beta-y)~~~~~~~(2)\]

From (1) and (2) we get,

\[B(y+\alpha,\,n+\beta-y)=\sum_{i=0}^{\infty}(-1)^{i}{\beta-1\choose i}B(y+\alpha+i,\,n-y+1)\]

provided, \(Re(y+\alpha)>0,\,Re(n-y+1)>0\mbox{ and }Re(n+\beta-y)>0\)

Kind Regards,
Sudharaka.
 
Hi chamilka! Welcome to MHB! :)

I think you should be able to send PM's now so I've removed your replies to Sudharaka from public view. I can copy the posts to you through PM if you would like. The minimum post counts can be annoying I know, but they stop others from doing a lot of things that waste MHB's time so they are there for a reason. You should be able to use most of the functionality of the site already and if not only need a couple more posts. Let me know if I can help you in any way.

Jameson
 
Thank you Jameson for your kind support. I am very lucky to be a mart of Math Help boards.
 

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