MHB What are the key properties of the Generalized Beta Function and its integrals?

Click For Summary
The discussion focuses on the Generalized Beta Function defined by the integral $$\beta(a,b,c;s) = \int^1_0 \frac{1}{(1-x)^a(s-x)^b x^c}\, dx$$ with parameters constrained to -1<a,b,c<1 and s≥0. A key relationship is established with the standard beta function when s=1, leading to the formula $$\beta(a,b,c;1) = \frac{\Gamma(1-c)\Gamma(1-(a+b))}{\Gamma(2-(a+b+c))$$ under certain conditions on the real parts of the parameters. Suggestions for further exploration include using the reflection substitution $$x \to 1-x$$ and considering partial derivatives with respect to the parameters. The thread encourages contributions and insights on the properties and integrals of the Generalized Beta Function. Overall, it serves as a platform for deeper mathematical exploration of this function's characteristics.
alyafey22
Gold Member
MHB
Messages
1,556
Reaction score
2
In this thread we consider the integrals of the form

$$\beta(a,b,c;s) = \int^1_0 \frac{1}{(1-x)^a(s-x)^b x^c}\, dx \,\,\,\,\,\,-1<a,b,c<1 \,\,\,s\geq 0 $$

This is NOT a tutorial , all suggestions are encouraged.
 
Physics news on Phys.org
We can relate it to the beta function $$s=1$$
Assume $$\Re(a+b)>0 , \Re(1-c)>0$$

$$\beta(a,b,c;\,1) = \int^1_0 (1-x)^{-(a+b)} x^{-c}dx= \beta(1-c,1-(a+b))=\frac{\Gamma(1-c)\Gamma(1-(a+b))}{\Gamma(2-(a+b+c))}$$

$$\tag{1} \beta(a,b,c;\,1) = \frac{\Gamma(1-c)\Gamma(1-(a+b))}{\Gamma(2-(a+b+c))} \,\,\,\, \Re(a+b)>0 , \Re(1-c)>0$$​
 
ZaidAlyafey said:
In this thread we consider the integrals of the form

$$\beta(a,b,c;s) = \int^1_0 \frac{1}{(1-x)^a(s-x)^b x^c}\, dx \,\,\,\,\,\,-1<a,b,c<1 \,\,\,s\geq 0 $$

This is NOT a tutorial , all suggestions are encouraged.
You're on tip-top form, Zaid! I like it! (Heidy)

A few things jump out at me, which might be worth exploring...

Firstly, the reflection substitution $$x \to 1-x$$ might be worth a look... Also, being the logarithmic fiend that I am, I think it might be worth considering partial derivatives wrt any/all of the parameters.

I'll definitely come back to this topic when it's not so close to bed time. Very interesting! (heart)
 
Thread 'Problem with calculating projections of curl using rotation of contour'
Hello! I tried to calculate projections of curl using rotation of coordinate system but I encountered with following problem. Given: ##rot_xA=\frac{\partial A_z}{\partial y}-\frac{\partial A_y}{\partial z}=0## ##rot_yA=\frac{\partial A_x}{\partial z}-\frac{\partial A_z}{\partial x}=1## ##rot_zA=\frac{\partial A_y}{\partial x}-\frac{\partial A_x}{\partial y}=0## I rotated ##yz##-plane of this coordinate system by an angle ##45## degrees about ##x##-axis and used rotation matrix to...

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 200 ·
7
Replies
200
Views
28K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K