Is it Possible to show this? Beta function

In summary, Sudharaka showed that the integral \(int_{0}^{1}x^{y+\alpha-1}(1-x)^{(n+\beta-y)-1}\,dx\) can be solved by using the properties of beta functions and Gaussian hypergeometric function.
  • #1
chamilka
9
0
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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  • #2
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.
 
  • #3
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
 
  • #4
Thank you Jameson for your kind support. I am very lucky to be a mart of Math Help boards.
 

FAQ: Is it Possible to show this? Beta function

What is the beta function?

The beta function is a mathematical function that is used to represent the relationship between two variables, typically denoted by the Greek letters alpha and beta. It is often used in statistics and probability theory to calculate the probability density function for continuous random variables.

What is the significance of the beta function?

The beta function has several important applications in mathematics, physics, and engineering. It is commonly used in the calculation of integrals, as well as in the derivation of other mathematical functions such as the gamma function. It also has uses in statistical analysis, particularly in the field of Bayesian statistics.

Is it possible to show the beta function graphically?

Yes, it is possible to graph the beta function. However, the shape of the graph will vary depending on the values of the two variables, alpha and beta. In general, the beta function graph will have a smooth, curved shape that resembles a bell curve.

What is the relationship between the beta function and the gamma function?

The beta function and the gamma function are closely related. In fact, the beta function can be expressed in terms of the gamma function, and vice versa. This relationship is often used in mathematical proofs and derivations.

Are there any real-world applications of the beta function?

Yes, the beta function has many real-world applications. It is commonly used in fields such as physics, biology, and economics to model and analyze various phenomena. For example, the beta function can be used to calculate the distribution of particle energy in a gas, or to model the distribution of genetic traits in a population.

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