Limit of $ln(x)-sumlimits_x=1^inftyleft( fracpi²6 - sumlimits_x=1^infty frac1x²right)$ [closed]

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I did my best to get the notation correct but it is likely wrong so let me explain. The sum on the right tends to $fracpi²6$. As it is incrementally getting closer to $fracpi²6$ I want to see what the delta is to $fracpi²6$ and I would like to sum those deltas. I noticed this sum is a very close approximation to $ln(x)$ but it tends to be off by ~.0677. The 0677 is the limit of where my excel skills can get me but I want to find out if this actually tends to a specific number or if it goes up forever. I have gone through $x=1$ to $1,000,000$. Is there a way to put this into wolfram alpha?



$$ln(x)-displaystylesum_x=1^infty( fracpi²6 - displaystylesum_x=1^infty frac1x²)=?$$







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closed as unclear what you're asking by Batominovski, Taroccoesbrocco, amWhy, Henrik, max_zorn Aug 12 at 0:05


Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.










  • 1




    The notation doesn't make much sense...both summations are over the same variable, so the summation is not well defined.
    – Rushabh Mehta
    Aug 10 at 20:02






  • 5




    Are you rather after something like $$S_n=ln(n)-sum_k=1^nleft( fracpi^26-sum_i=1^kfrac1i^2right) ?$$ Then this is also $$S_n=ln(n)-sum_k=1^nsum_i=k+1^inftyfrac1i^2$$ and one can indeed show that, $S_n$ converges to a finite limit when $ntoinfty$.
    – Did
    Aug 10 at 20:06














up vote
-3
down vote

favorite












I did my best to get the notation correct but it is likely wrong so let me explain. The sum on the right tends to $fracpi²6$. As it is incrementally getting closer to $fracpi²6$ I want to see what the delta is to $fracpi²6$ and I would like to sum those deltas. I noticed this sum is a very close approximation to $ln(x)$ but it tends to be off by ~.0677. The 0677 is the limit of where my excel skills can get me but I want to find out if this actually tends to a specific number or if it goes up forever. I have gone through $x=1$ to $1,000,000$. Is there a way to put this into wolfram alpha?



$$ln(x)-displaystylesum_x=1^infty( fracpi²6 - displaystylesum_x=1^infty frac1x²)=?$$







share|cite|improve this question














closed as unclear what you're asking by Batominovski, Taroccoesbrocco, amWhy, Henrik, max_zorn Aug 12 at 0:05


Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.










  • 1




    The notation doesn't make much sense...both summations are over the same variable, so the summation is not well defined.
    – Rushabh Mehta
    Aug 10 at 20:02






  • 5




    Are you rather after something like $$S_n=ln(n)-sum_k=1^nleft( fracpi^26-sum_i=1^kfrac1i^2right) ?$$ Then this is also $$S_n=ln(n)-sum_k=1^nsum_i=k+1^inftyfrac1i^2$$ and one can indeed show that, $S_n$ converges to a finite limit when $ntoinfty$.
    – Did
    Aug 10 at 20:06












up vote
-3
down vote

favorite









up vote
-3
down vote

favorite











I did my best to get the notation correct but it is likely wrong so let me explain. The sum on the right tends to $fracpi²6$. As it is incrementally getting closer to $fracpi²6$ I want to see what the delta is to $fracpi²6$ and I would like to sum those deltas. I noticed this sum is a very close approximation to $ln(x)$ but it tends to be off by ~.0677. The 0677 is the limit of where my excel skills can get me but I want to find out if this actually tends to a specific number or if it goes up forever. I have gone through $x=1$ to $1,000,000$. Is there a way to put this into wolfram alpha?



$$ln(x)-displaystylesum_x=1^infty( fracpi²6 - displaystylesum_x=1^infty frac1x²)=?$$







share|cite|improve this question














I did my best to get the notation correct but it is likely wrong so let me explain. The sum on the right tends to $fracpi²6$. As it is incrementally getting closer to $fracpi²6$ I want to see what the delta is to $fracpi²6$ and I would like to sum those deltas. I noticed this sum is a very close approximation to $ln(x)$ but it tends to be off by ~.0677. The 0677 is the limit of where my excel skills can get me but I want to find out if this actually tends to a specific number or if it goes up forever. I have gone through $x=1$ to $1,000,000$. Is there a way to put this into wolfram alpha?



$$ln(x)-displaystylesum_x=1^infty( fracpi²6 - displaystylesum_x=1^infty frac1x²)=?$$









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edited Aug 10 at 20:07









Did

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242k23208443










asked Aug 10 at 19:55









Joe

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283112




closed as unclear what you're asking by Batominovski, Taroccoesbrocco, amWhy, Henrik, max_zorn Aug 12 at 0:05


Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.






closed as unclear what you're asking by Batominovski, Taroccoesbrocco, amWhy, Henrik, max_zorn Aug 12 at 0:05


Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.









  • 1




    The notation doesn't make much sense...both summations are over the same variable, so the summation is not well defined.
    – Rushabh Mehta
    Aug 10 at 20:02






  • 5




    Are you rather after something like $$S_n=ln(n)-sum_k=1^nleft( fracpi^26-sum_i=1^kfrac1i^2right) ?$$ Then this is also $$S_n=ln(n)-sum_k=1^nsum_i=k+1^inftyfrac1i^2$$ and one can indeed show that, $S_n$ converges to a finite limit when $ntoinfty$.
    – Did
    Aug 10 at 20:06












  • 1




    The notation doesn't make much sense...both summations are over the same variable, so the summation is not well defined.
    – Rushabh Mehta
    Aug 10 at 20:02






  • 5




    Are you rather after something like $$S_n=ln(n)-sum_k=1^nleft( fracpi^26-sum_i=1^kfrac1i^2right) ?$$ Then this is also $$S_n=ln(n)-sum_k=1^nsum_i=k+1^inftyfrac1i^2$$ and one can indeed show that, $S_n$ converges to a finite limit when $ntoinfty$.
    – Did
    Aug 10 at 20:06







1




1




The notation doesn't make much sense...both summations are over the same variable, so the summation is not well defined.
– Rushabh Mehta
Aug 10 at 20:02




The notation doesn't make much sense...both summations are over the same variable, so the summation is not well defined.
– Rushabh Mehta
Aug 10 at 20:02




5




5




Are you rather after something like $$S_n=ln(n)-sum_k=1^nleft( fracpi^26-sum_i=1^kfrac1i^2right) ?$$ Then this is also $$S_n=ln(n)-sum_k=1^nsum_i=k+1^inftyfrac1i^2$$ and one can indeed show that, $S_n$ converges to a finite limit when $ntoinfty$.
– Did
Aug 10 at 20:06




Are you rather after something like $$S_n=ln(n)-sum_k=1^nleft( fracpi^26-sum_i=1^kfrac1i^2right) ?$$ Then this is also $$S_n=ln(n)-sum_k=1^nsum_i=k+1^inftyfrac1i^2$$ and one can indeed show that, $S_n$ converges to a finite limit when $ntoinfty$.
– Did
Aug 10 at 20:06










2 Answers
2






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up vote
3
down vote



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Your notation does not make much sense, but trying to interpolate your actual question you seem to ask about the value of the limit
$$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]$$
where by summation by parts
$$ sum_k=1^nH_k^(2) = n H_n^(2)-sum_k=1^n-1frack(k+1)^2=(n+1) H_n^(2)-H_n $$
such that
$$ sum_k=1^nleft(zeta(2)-H_k^(2)right) = nleft(zeta(2)-H_n^(2)right)-H_n^(2)+H_n. $$
Now $lim_nto +inftyH_n^(2)=zeta(2)$ and $lim_nto +inftyleft(H_n-log(n)right)=gamma$. By Cesàro-Stolz
$$ lim_nto +inftyfraczeta(2)-H_n^(2)frac1n=lim_nto +inftyfracfrac1(n+1)^2frac1n(n+1)=1$$
hence
$$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]=colorredzeta(2)-gamma-1approx 0.0677184.$$






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    up vote
    0
    down vote













    Using Jack D'Aurizio's solution, we end with
    $$S_n=log(n)+H_n+1-(n+1), H_n+1^(2)+fracpi ^2 6n$$ Using the asymptotics of harmonic numbers, this leads to
    $$S_n=left(fracpi ^26-gamma-1right)-frac1n+frac512
    n^2+Oleft(frac1n^3right)$$ which shows the limit and how it is approached.



    Moreover, this gives a quite good approximation of $S_n$; for example,
    $$S_10=frac3586319254016-frac5 pi ^23+log (10)approx -0.0282788$$ while the above expansion leads to
    $$-frac263240-gamma +fracpi ^26approx -0.0281149$$






    share|cite|improve this answer



























      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes








      up vote
      3
      down vote



      accepted










      Your notation does not make much sense, but trying to interpolate your actual question you seem to ask about the value of the limit
      $$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]$$
      where by summation by parts
      $$ sum_k=1^nH_k^(2) = n H_n^(2)-sum_k=1^n-1frack(k+1)^2=(n+1) H_n^(2)-H_n $$
      such that
      $$ sum_k=1^nleft(zeta(2)-H_k^(2)right) = nleft(zeta(2)-H_n^(2)right)-H_n^(2)+H_n. $$
      Now $lim_nto +inftyH_n^(2)=zeta(2)$ and $lim_nto +inftyleft(H_n-log(n)right)=gamma$. By Cesàro-Stolz
      $$ lim_nto +inftyfraczeta(2)-H_n^(2)frac1n=lim_nto +inftyfracfrac1(n+1)^2frac1n(n+1)=1$$
      hence
      $$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]=colorredzeta(2)-gamma-1approx 0.0677184.$$






      share|cite|improve this answer
























        up vote
        3
        down vote



        accepted










        Your notation does not make much sense, but trying to interpolate your actual question you seem to ask about the value of the limit
        $$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]$$
        where by summation by parts
        $$ sum_k=1^nH_k^(2) = n H_n^(2)-sum_k=1^n-1frack(k+1)^2=(n+1) H_n^(2)-H_n $$
        such that
        $$ sum_k=1^nleft(zeta(2)-H_k^(2)right) = nleft(zeta(2)-H_n^(2)right)-H_n^(2)+H_n. $$
        Now $lim_nto +inftyH_n^(2)=zeta(2)$ and $lim_nto +inftyleft(H_n-log(n)right)=gamma$. By Cesàro-Stolz
        $$ lim_nto +inftyfraczeta(2)-H_n^(2)frac1n=lim_nto +inftyfracfrac1(n+1)^2frac1n(n+1)=1$$
        hence
        $$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]=colorredzeta(2)-gamma-1approx 0.0677184.$$






        share|cite|improve this answer






















          up vote
          3
          down vote



          accepted







          up vote
          3
          down vote



          accepted






          Your notation does not make much sense, but trying to interpolate your actual question you seem to ask about the value of the limit
          $$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]$$
          where by summation by parts
          $$ sum_k=1^nH_k^(2) = n H_n^(2)-sum_k=1^n-1frack(k+1)^2=(n+1) H_n^(2)-H_n $$
          such that
          $$ sum_k=1^nleft(zeta(2)-H_k^(2)right) = nleft(zeta(2)-H_n^(2)right)-H_n^(2)+H_n. $$
          Now $lim_nto +inftyH_n^(2)=zeta(2)$ and $lim_nto +inftyleft(H_n-log(n)right)=gamma$. By Cesàro-Stolz
          $$ lim_nto +inftyfraczeta(2)-H_n^(2)frac1n=lim_nto +inftyfracfrac1(n+1)^2frac1n(n+1)=1$$
          hence
          $$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]=colorredzeta(2)-gamma-1approx 0.0677184.$$






          share|cite|improve this answer












          Your notation does not make much sense, but trying to interpolate your actual question you seem to ask about the value of the limit
          $$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]$$
          where by summation by parts
          $$ sum_k=1^nH_k^(2) = n H_n^(2)-sum_k=1^n-1frack(k+1)^2=(n+1) H_n^(2)-H_n $$
          such that
          $$ sum_k=1^nleft(zeta(2)-H_k^(2)right) = nleft(zeta(2)-H_n^(2)right)-H_n^(2)+H_n. $$
          Now $lim_nto +inftyH_n^(2)=zeta(2)$ and $lim_nto +inftyleft(H_n-log(n)right)=gamma$. By Cesàro-Stolz
          $$ lim_nto +inftyfraczeta(2)-H_n^(2)frac1n=lim_nto +inftyfracfrac1(n+1)^2frac1n(n+1)=1$$
          hence
          $$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]=colorredzeta(2)-gamma-1approx 0.0677184.$$







          share|cite|improve this answer












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          answered Aug 10 at 20:32









          Jack D'Aurizio♦

          271k31266632




          271k31266632




















              up vote
              0
              down vote













              Using Jack D'Aurizio's solution, we end with
              $$S_n=log(n)+H_n+1-(n+1), H_n+1^(2)+fracpi ^2 6n$$ Using the asymptotics of harmonic numbers, this leads to
              $$S_n=left(fracpi ^26-gamma-1right)-frac1n+frac512
              n^2+Oleft(frac1n^3right)$$ which shows the limit and how it is approached.



              Moreover, this gives a quite good approximation of $S_n$; for example,
              $$S_10=frac3586319254016-frac5 pi ^23+log (10)approx -0.0282788$$ while the above expansion leads to
              $$-frac263240-gamma +fracpi ^26approx -0.0281149$$






              share|cite|improve this answer
























                up vote
                0
                down vote













                Using Jack D'Aurizio's solution, we end with
                $$S_n=log(n)+H_n+1-(n+1), H_n+1^(2)+fracpi ^2 6n$$ Using the asymptotics of harmonic numbers, this leads to
                $$S_n=left(fracpi ^26-gamma-1right)-frac1n+frac512
                n^2+Oleft(frac1n^3right)$$ which shows the limit and how it is approached.



                Moreover, this gives a quite good approximation of $S_n$; for example,
                $$S_10=frac3586319254016-frac5 pi ^23+log (10)approx -0.0282788$$ while the above expansion leads to
                $$-frac263240-gamma +fracpi ^26approx -0.0281149$$






                share|cite|improve this answer






















                  up vote
                  0
                  down vote










                  up vote
                  0
                  down vote









                  Using Jack D'Aurizio's solution, we end with
                  $$S_n=log(n)+H_n+1-(n+1), H_n+1^(2)+fracpi ^2 6n$$ Using the asymptotics of harmonic numbers, this leads to
                  $$S_n=left(fracpi ^26-gamma-1right)-frac1n+frac512
                  n^2+Oleft(frac1n^3right)$$ which shows the limit and how it is approached.



                  Moreover, this gives a quite good approximation of $S_n$; for example,
                  $$S_10=frac3586319254016-frac5 pi ^23+log (10)approx -0.0282788$$ while the above expansion leads to
                  $$-frac263240-gamma +fracpi ^26approx -0.0281149$$






                  share|cite|improve this answer












                  Using Jack D'Aurizio's solution, we end with
                  $$S_n=log(n)+H_n+1-(n+1), H_n+1^(2)+fracpi ^2 6n$$ Using the asymptotics of harmonic numbers, this leads to
                  $$S_n=left(fracpi ^26-gamma-1right)-frac1n+frac512
                  n^2+Oleft(frac1n^3right)$$ which shows the limit and how it is approached.



                  Moreover, this gives a quite good approximation of $S_n$; for example,
                  $$S_10=frac3586319254016-frac5 pi ^23+log (10)approx -0.0282788$$ while the above expansion leads to
                  $$-frac263240-gamma +fracpi ^26approx -0.0281149$$







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered Aug 11 at 4:59









                  Claude Leibovici

                  112k1055126




                  112k1055126












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