Integral involving the logarithm












0














Let $p$ and $q$ be two positive integers, I wonder if the following integral admits a closed-form and if yeah so in which way it should be worked out.



$$int_{0}^{1}frac{ln(1-x^p)ln(1+x^q)}{x^{p+q}}dx,=sum_{n,kgeq1}frac{(-1)^n}{nk(np+kq+1-p-q)}$$










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  • What have you tried by yourself?
    – mrtaurho
    2 days ago










  • using Tylor series of $ln(1-x^q)$ and $ln(1+x^p)$
    – Kays Tomy
    2 days ago










  • What have you found so far from your attempts?
    – clathratus
    2 days ago










  • Alternating series as it is shown above
    – Kays Tomy
    2 days ago
















0














Let $p$ and $q$ be two positive integers, I wonder if the following integral admits a closed-form and if yeah so in which way it should be worked out.



$$int_{0}^{1}frac{ln(1-x^p)ln(1+x^q)}{x^{p+q}}dx,=sum_{n,kgeq1}frac{(-1)^n}{nk(np+kq+1-p-q)}$$










share|cite|improve this question
























  • What have you tried by yourself?
    – mrtaurho
    2 days ago










  • using Tylor series of $ln(1-x^q)$ and $ln(1+x^p)$
    – Kays Tomy
    2 days ago










  • What have you found so far from your attempts?
    – clathratus
    2 days ago










  • Alternating series as it is shown above
    – Kays Tomy
    2 days ago














0












0








0


3





Let $p$ and $q$ be two positive integers, I wonder if the following integral admits a closed-form and if yeah so in which way it should be worked out.



$$int_{0}^{1}frac{ln(1-x^p)ln(1+x^q)}{x^{p+q}}dx,=sum_{n,kgeq1}frac{(-1)^n}{nk(np+kq+1-p-q)}$$










share|cite|improve this question















Let $p$ and $q$ be two positive integers, I wonder if the following integral admits a closed-form and if yeah so in which way it should be worked out.



$$int_{0}^{1}frac{ln(1-x^p)ln(1+x^q)}{x^{p+q}}dx,=sum_{n,kgeq1}frac{(-1)^n}{nk(np+kq+1-p-q)}$$







integration definite-integrals power-series






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edited 2 days ago









Masacroso

12.9k41746




12.9k41746










asked 2 days ago









Kays Tomy

1977




1977












  • What have you tried by yourself?
    – mrtaurho
    2 days ago










  • using Tylor series of $ln(1-x^q)$ and $ln(1+x^p)$
    – Kays Tomy
    2 days ago










  • What have you found so far from your attempts?
    – clathratus
    2 days ago










  • Alternating series as it is shown above
    – Kays Tomy
    2 days ago


















  • What have you tried by yourself?
    – mrtaurho
    2 days ago










  • using Tylor series of $ln(1-x^q)$ and $ln(1+x^p)$
    – Kays Tomy
    2 days ago










  • What have you found so far from your attempts?
    – clathratus
    2 days ago










  • Alternating series as it is shown above
    – Kays Tomy
    2 days ago
















What have you tried by yourself?
– mrtaurho
2 days ago




What have you tried by yourself?
– mrtaurho
2 days ago












using Tylor series of $ln(1-x^q)$ and $ln(1+x^p)$
– Kays Tomy
2 days ago




using Tylor series of $ln(1-x^q)$ and $ln(1+x^p)$
– Kays Tomy
2 days ago












What have you found so far from your attempts?
– clathratus
2 days ago




What have you found so far from your attempts?
– clathratus
2 days ago












Alternating series as it is shown above
– Kays Tomy
2 days ago




Alternating series as it is shown above
– Kays Tomy
2 days ago










1 Answer
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Here is a partial answer in terms of an infinite series. After expanding both logarithms into their respective Maclaurin series, integrating term by term and applying a certain series representation of the digamma function, I've obtained this series:
$$int_0^1 frac{log(1-x^p)log(1+x^q)}{x^{p+q}},dx=sum_{kge 0} (-1)^{k+1} frac{psi^{(0)}left(frac{kq+1}{p}right)+gamma}{(k+1)(kq-p+1)}$$
Where $psi^{(0)}$ $(=Gamma'/Gamma )$ is the digamma function and $gamma$ ($=lim_{ntoinfty} H_n-log n$) is the Euler-Mascheroni constant. I'm not sure how to simplify this sum, which appears especially challenging because of the appearance of digamma function.



Checking the basic case $q=0$ yields
$$int_0^1 frac{log(1-x^p)}{x^p},dx=frac{psi^{(0)}(1/p)+gamma}{p-1}$$
Which seems to agree with some of the computational verifications I've done.






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    1 Answer
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    1 Answer
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    active

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    0














    Here is a partial answer in terms of an infinite series. After expanding both logarithms into their respective Maclaurin series, integrating term by term and applying a certain series representation of the digamma function, I've obtained this series:
    $$int_0^1 frac{log(1-x^p)log(1+x^q)}{x^{p+q}},dx=sum_{kge 0} (-1)^{k+1} frac{psi^{(0)}left(frac{kq+1}{p}right)+gamma}{(k+1)(kq-p+1)}$$
    Where $psi^{(0)}$ $(=Gamma'/Gamma )$ is the digamma function and $gamma$ ($=lim_{ntoinfty} H_n-log n$) is the Euler-Mascheroni constant. I'm not sure how to simplify this sum, which appears especially challenging because of the appearance of digamma function.



    Checking the basic case $q=0$ yields
    $$int_0^1 frac{log(1-x^p)}{x^p},dx=frac{psi^{(0)}(1/p)+gamma}{p-1}$$
    Which seems to agree with some of the computational verifications I've done.






    share|cite|improve this answer


























      0














      Here is a partial answer in terms of an infinite series. After expanding both logarithms into their respective Maclaurin series, integrating term by term and applying a certain series representation of the digamma function, I've obtained this series:
      $$int_0^1 frac{log(1-x^p)log(1+x^q)}{x^{p+q}},dx=sum_{kge 0} (-1)^{k+1} frac{psi^{(0)}left(frac{kq+1}{p}right)+gamma}{(k+1)(kq-p+1)}$$
      Where $psi^{(0)}$ $(=Gamma'/Gamma )$ is the digamma function and $gamma$ ($=lim_{ntoinfty} H_n-log n$) is the Euler-Mascheroni constant. I'm not sure how to simplify this sum, which appears especially challenging because of the appearance of digamma function.



      Checking the basic case $q=0$ yields
      $$int_0^1 frac{log(1-x^p)}{x^p},dx=frac{psi^{(0)}(1/p)+gamma}{p-1}$$
      Which seems to agree with some of the computational verifications I've done.






      share|cite|improve this answer
























        0












        0








        0






        Here is a partial answer in terms of an infinite series. After expanding both logarithms into their respective Maclaurin series, integrating term by term and applying a certain series representation of the digamma function, I've obtained this series:
        $$int_0^1 frac{log(1-x^p)log(1+x^q)}{x^{p+q}},dx=sum_{kge 0} (-1)^{k+1} frac{psi^{(0)}left(frac{kq+1}{p}right)+gamma}{(k+1)(kq-p+1)}$$
        Where $psi^{(0)}$ $(=Gamma'/Gamma )$ is the digamma function and $gamma$ ($=lim_{ntoinfty} H_n-log n$) is the Euler-Mascheroni constant. I'm not sure how to simplify this sum, which appears especially challenging because of the appearance of digamma function.



        Checking the basic case $q=0$ yields
        $$int_0^1 frac{log(1-x^p)}{x^p},dx=frac{psi^{(0)}(1/p)+gamma}{p-1}$$
        Which seems to agree with some of the computational verifications I've done.






        share|cite|improve this answer












        Here is a partial answer in terms of an infinite series. After expanding both logarithms into their respective Maclaurin series, integrating term by term and applying a certain series representation of the digamma function, I've obtained this series:
        $$int_0^1 frac{log(1-x^p)log(1+x^q)}{x^{p+q}},dx=sum_{kge 0} (-1)^{k+1} frac{psi^{(0)}left(frac{kq+1}{p}right)+gamma}{(k+1)(kq-p+1)}$$
        Where $psi^{(0)}$ $(=Gamma'/Gamma )$ is the digamma function and $gamma$ ($=lim_{ntoinfty} H_n-log n$) is the Euler-Mascheroni constant. I'm not sure how to simplify this sum, which appears especially challenging because of the appearance of digamma function.



        Checking the basic case $q=0$ yields
        $$int_0^1 frac{log(1-x^p)}{x^p},dx=frac{psi^{(0)}(1/p)+gamma}{p-1}$$
        Which seems to agree with some of the computational verifications I've done.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered 2 days ago









        Zachary

        2,2891211




        2,2891211






























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