Simplifying the division of integrals

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Is there a way to simplify this division of integrals, or at least find a bound for it, without writing it in terms of CDF of Beta?



I tried to use the idea here but didn't have much luck.



$$fracint_l^u x^a (1-x)^b-1 ;dxint_l^u x^a-1 (1-x)^b-1 ; dx$$







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  • Are ther any restrictions for $l$ and $u$? Because if $l=0$ and $u=1$ you could rewrite this fraction using Beta or Gamma functions. Or, without these conditions, maybe in terms of the incomplete Beta function. I have asked similiar question by myself and I would be interested in an answer too.
    – mrtaurho
    Jul 23 at 22:14







  • 1




    @mrtaurho $l >0$ and $u < 1$.
    – mathlover
    Jul 23 at 22:19










  • Doesn't the identity $$int_l^u x^a (1-x)^b-1 , dx=int_l^u x^a-1 (1-x)^b-1 , dx-int_l^u x^a-1 (1-x)^b , dx$$, and that the integrals are all positive, imply that the division of the above integrals is bounded between 0 and 1?
    – James Arathoon
    Jul 24 at 23:59














up vote
1
down vote

favorite












Is there a way to simplify this division of integrals, or at least find a bound for it, without writing it in terms of CDF of Beta?



I tried to use the idea here but didn't have much luck.



$$fracint_l^u x^a (1-x)^b-1 ;dxint_l^u x^a-1 (1-x)^b-1 ; dx$$







share|cite|improve this question





















  • Are ther any restrictions for $l$ and $u$? Because if $l=0$ and $u=1$ you could rewrite this fraction using Beta or Gamma functions. Or, without these conditions, maybe in terms of the incomplete Beta function. I have asked similiar question by myself and I would be interested in an answer too.
    – mrtaurho
    Jul 23 at 22:14







  • 1




    @mrtaurho $l >0$ and $u < 1$.
    – mathlover
    Jul 23 at 22:19










  • Doesn't the identity $$int_l^u x^a (1-x)^b-1 , dx=int_l^u x^a-1 (1-x)^b-1 , dx-int_l^u x^a-1 (1-x)^b , dx$$, and that the integrals are all positive, imply that the division of the above integrals is bounded between 0 and 1?
    – James Arathoon
    Jul 24 at 23:59












up vote
1
down vote

favorite









up vote
1
down vote

favorite











Is there a way to simplify this division of integrals, or at least find a bound for it, without writing it in terms of CDF of Beta?



I tried to use the idea here but didn't have much luck.



$$fracint_l^u x^a (1-x)^b-1 ;dxint_l^u x^a-1 (1-x)^b-1 ; dx$$







share|cite|improve this question













Is there a way to simplify this division of integrals, or at least find a bound for it, without writing it in terms of CDF of Beta?



I tried to use the idea here but didn't have much luck.



$$fracint_l^u x^a (1-x)^b-1 ;dxint_l^u x^a-1 (1-x)^b-1 ; dx$$









share|cite|improve this question












share|cite|improve this question




share|cite|improve this question








edited Jul 24 at 22:37
























asked Jul 23 at 22:08









mathlover

416




416











  • Are ther any restrictions for $l$ and $u$? Because if $l=0$ and $u=1$ you could rewrite this fraction using Beta or Gamma functions. Or, without these conditions, maybe in terms of the incomplete Beta function. I have asked similiar question by myself and I would be interested in an answer too.
    – mrtaurho
    Jul 23 at 22:14







  • 1




    @mrtaurho $l >0$ and $u < 1$.
    – mathlover
    Jul 23 at 22:19










  • Doesn't the identity $$int_l^u x^a (1-x)^b-1 , dx=int_l^u x^a-1 (1-x)^b-1 , dx-int_l^u x^a-1 (1-x)^b , dx$$, and that the integrals are all positive, imply that the division of the above integrals is bounded between 0 and 1?
    – James Arathoon
    Jul 24 at 23:59
















  • Are ther any restrictions for $l$ and $u$? Because if $l=0$ and $u=1$ you could rewrite this fraction using Beta or Gamma functions. Or, without these conditions, maybe in terms of the incomplete Beta function. I have asked similiar question by myself and I would be interested in an answer too.
    – mrtaurho
    Jul 23 at 22:14







  • 1




    @mrtaurho $l >0$ and $u < 1$.
    – mathlover
    Jul 23 at 22:19










  • Doesn't the identity $$int_l^u x^a (1-x)^b-1 , dx=int_l^u x^a-1 (1-x)^b-1 , dx-int_l^u x^a-1 (1-x)^b , dx$$, and that the integrals are all positive, imply that the division of the above integrals is bounded between 0 and 1?
    – James Arathoon
    Jul 24 at 23:59















Are ther any restrictions for $l$ and $u$? Because if $l=0$ and $u=1$ you could rewrite this fraction using Beta or Gamma functions. Or, without these conditions, maybe in terms of the incomplete Beta function. I have asked similiar question by myself and I would be interested in an answer too.
– mrtaurho
Jul 23 at 22:14





Are ther any restrictions for $l$ and $u$? Because if $l=0$ and $u=1$ you could rewrite this fraction using Beta or Gamma functions. Or, without these conditions, maybe in terms of the incomplete Beta function. I have asked similiar question by myself and I would be interested in an answer too.
– mrtaurho
Jul 23 at 22:14





1




1




@mrtaurho $l >0$ and $u < 1$.
– mathlover
Jul 23 at 22:19




@mrtaurho $l >0$ and $u < 1$.
– mathlover
Jul 23 at 22:19












Doesn't the identity $$int_l^u x^a (1-x)^b-1 , dx=int_l^u x^a-1 (1-x)^b-1 , dx-int_l^u x^a-1 (1-x)^b , dx$$, and that the integrals are all positive, imply that the division of the above integrals is bounded between 0 and 1?
– James Arathoon
Jul 24 at 23:59




Doesn't the identity $$int_l^u x^a (1-x)^b-1 , dx=int_l^u x^a-1 (1-x)^b-1 , dx-int_l^u x^a-1 (1-x)^b , dx$$, and that the integrals are all positive, imply that the division of the above integrals is bounded between 0 and 1?
– James Arathoon
Jul 24 at 23:59










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I would try it as follows:



$$int_l^u x^a(1-x)^b-1mathrmdx~=~int_0^u x^a(1-x)^b-1mathrmdx~-~int_0^l x^a(1-x)^b-1mathrmdx$$



$$int_l^u x^a-1(1-x)^b-1mathrmdx~=~int_0^u x^a-1(1-x)^b-1mathrmdx~-~int_0^l x^a-1(1-x)^b-1mathrmdx$$



With the incomplete Beta function



$$B(x; a,b)~=~ int_0^x x^a-1(1-x)^b-1mathrmdx$$



The fraction would become



$$beginalignfracint_l^u x^a(1-x)^b-1mathrmdxint_l^u x^a-1(1-x)^b-1mathrmdx~&=~fracint_0^u x^a(1-x)^b-1mathrmdx~-~int_0^l x^a(1-x)^b-1mathrmdxint_0^u x^a-1(1-x)^b-1mathrmdx~-~int_0^l x^a-1(1-x)^b-1mathrmdx\~&=~fracB(u;a+1,b)-B(l;a+1,b)B(u;a,b)-B(l;a,b)endalign$$



First of all I am not sure if this is even possible to do so in this way and on the other hand I am not sure if this helps.



I do not know another way without the incomplete Beta function.






share|cite|improve this answer





















  • Thanks. I was aware of this way of derivation(I mentioned in the question without using CDF of beta). I'm interested in another way without using the incomplete beta.
    – mathlover
    Jul 23 at 23:31










  • I just realized it afterwards. I am not familiar with another of simplification but as I already mentioned I would be interested in one too.
    – mrtaurho
    Jul 23 at 23:34










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1 Answer
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I would try it as follows:



$$int_l^u x^a(1-x)^b-1mathrmdx~=~int_0^u x^a(1-x)^b-1mathrmdx~-~int_0^l x^a(1-x)^b-1mathrmdx$$



$$int_l^u x^a-1(1-x)^b-1mathrmdx~=~int_0^u x^a-1(1-x)^b-1mathrmdx~-~int_0^l x^a-1(1-x)^b-1mathrmdx$$



With the incomplete Beta function



$$B(x; a,b)~=~ int_0^x x^a-1(1-x)^b-1mathrmdx$$



The fraction would become



$$beginalignfracint_l^u x^a(1-x)^b-1mathrmdxint_l^u x^a-1(1-x)^b-1mathrmdx~&=~fracint_0^u x^a(1-x)^b-1mathrmdx~-~int_0^l x^a(1-x)^b-1mathrmdxint_0^u x^a-1(1-x)^b-1mathrmdx~-~int_0^l x^a-1(1-x)^b-1mathrmdx\~&=~fracB(u;a+1,b)-B(l;a+1,b)B(u;a,b)-B(l;a,b)endalign$$



First of all I am not sure if this is even possible to do so in this way and on the other hand I am not sure if this helps.



I do not know another way without the incomplete Beta function.






share|cite|improve this answer





















  • Thanks. I was aware of this way of derivation(I mentioned in the question without using CDF of beta). I'm interested in another way without using the incomplete beta.
    – mathlover
    Jul 23 at 23:31










  • I just realized it afterwards. I am not familiar with another of simplification but as I already mentioned I would be interested in one too.
    – mrtaurho
    Jul 23 at 23:34














up vote
1
down vote













I would try it as follows:



$$int_l^u x^a(1-x)^b-1mathrmdx~=~int_0^u x^a(1-x)^b-1mathrmdx~-~int_0^l x^a(1-x)^b-1mathrmdx$$



$$int_l^u x^a-1(1-x)^b-1mathrmdx~=~int_0^u x^a-1(1-x)^b-1mathrmdx~-~int_0^l x^a-1(1-x)^b-1mathrmdx$$



With the incomplete Beta function



$$B(x; a,b)~=~ int_0^x x^a-1(1-x)^b-1mathrmdx$$



The fraction would become



$$beginalignfracint_l^u x^a(1-x)^b-1mathrmdxint_l^u x^a-1(1-x)^b-1mathrmdx~&=~fracint_0^u x^a(1-x)^b-1mathrmdx~-~int_0^l x^a(1-x)^b-1mathrmdxint_0^u x^a-1(1-x)^b-1mathrmdx~-~int_0^l x^a-1(1-x)^b-1mathrmdx\~&=~fracB(u;a+1,b)-B(l;a+1,b)B(u;a,b)-B(l;a,b)endalign$$



First of all I am not sure if this is even possible to do so in this way and on the other hand I am not sure if this helps.



I do not know another way without the incomplete Beta function.






share|cite|improve this answer





















  • Thanks. I was aware of this way of derivation(I mentioned in the question without using CDF of beta). I'm interested in another way without using the incomplete beta.
    – mathlover
    Jul 23 at 23:31










  • I just realized it afterwards. I am not familiar with another of simplification but as I already mentioned I would be interested in one too.
    – mrtaurho
    Jul 23 at 23:34












up vote
1
down vote










up vote
1
down vote









I would try it as follows:



$$int_l^u x^a(1-x)^b-1mathrmdx~=~int_0^u x^a(1-x)^b-1mathrmdx~-~int_0^l x^a(1-x)^b-1mathrmdx$$



$$int_l^u x^a-1(1-x)^b-1mathrmdx~=~int_0^u x^a-1(1-x)^b-1mathrmdx~-~int_0^l x^a-1(1-x)^b-1mathrmdx$$



With the incomplete Beta function



$$B(x; a,b)~=~ int_0^x x^a-1(1-x)^b-1mathrmdx$$



The fraction would become



$$beginalignfracint_l^u x^a(1-x)^b-1mathrmdxint_l^u x^a-1(1-x)^b-1mathrmdx~&=~fracint_0^u x^a(1-x)^b-1mathrmdx~-~int_0^l x^a(1-x)^b-1mathrmdxint_0^u x^a-1(1-x)^b-1mathrmdx~-~int_0^l x^a-1(1-x)^b-1mathrmdx\~&=~fracB(u;a+1,b)-B(l;a+1,b)B(u;a,b)-B(l;a,b)endalign$$



First of all I am not sure if this is even possible to do so in this way and on the other hand I am not sure if this helps.



I do not know another way without the incomplete Beta function.






share|cite|improve this answer













I would try it as follows:



$$int_l^u x^a(1-x)^b-1mathrmdx~=~int_0^u x^a(1-x)^b-1mathrmdx~-~int_0^l x^a(1-x)^b-1mathrmdx$$



$$int_l^u x^a-1(1-x)^b-1mathrmdx~=~int_0^u x^a-1(1-x)^b-1mathrmdx~-~int_0^l x^a-1(1-x)^b-1mathrmdx$$



With the incomplete Beta function



$$B(x; a,b)~=~ int_0^x x^a-1(1-x)^b-1mathrmdx$$



The fraction would become



$$beginalignfracint_l^u x^a(1-x)^b-1mathrmdxint_l^u x^a-1(1-x)^b-1mathrmdx~&=~fracint_0^u x^a(1-x)^b-1mathrmdx~-~int_0^l x^a(1-x)^b-1mathrmdxint_0^u x^a-1(1-x)^b-1mathrmdx~-~int_0^l x^a-1(1-x)^b-1mathrmdx\~&=~fracB(u;a+1,b)-B(l;a+1,b)B(u;a,b)-B(l;a,b)endalign$$



First of all I am not sure if this is even possible to do so in this way and on the other hand I am not sure if this helps.



I do not know another way without the incomplete Beta function.







share|cite|improve this answer













share|cite|improve this answer



share|cite|improve this answer











answered Jul 23 at 22:27









mrtaurho

750219




750219











  • Thanks. I was aware of this way of derivation(I mentioned in the question without using CDF of beta). I'm interested in another way without using the incomplete beta.
    – mathlover
    Jul 23 at 23:31










  • I just realized it afterwards. I am not familiar with another of simplification but as I already mentioned I would be interested in one too.
    – mrtaurho
    Jul 23 at 23:34
















  • Thanks. I was aware of this way of derivation(I mentioned in the question without using CDF of beta). I'm interested in another way without using the incomplete beta.
    – mathlover
    Jul 23 at 23:31










  • I just realized it afterwards. I am not familiar with another of simplification but as I already mentioned I would be interested in one too.
    – mrtaurho
    Jul 23 at 23:34















Thanks. I was aware of this way of derivation(I mentioned in the question without using CDF of beta). I'm interested in another way without using the incomplete beta.
– mathlover
Jul 23 at 23:31




Thanks. I was aware of this way of derivation(I mentioned in the question without using CDF of beta). I'm interested in another way without using the incomplete beta.
– mathlover
Jul 23 at 23:31












I just realized it afterwards. I am not familiar with another of simplification but as I already mentioned I would be interested in one too.
– mrtaurho
Jul 23 at 23:34




I just realized it afterwards. I am not familiar with another of simplification but as I already mentioned I would be interested in one too.
– mrtaurho
Jul 23 at 23:34












 

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