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 $fracpiò6$. As it is incrementally getting closer to $fracpiò6$ I want to see what the delta is to $fracpiò6$ 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?
$$ln(x)-displaystylesum_x=1^infty( fracpiò6 - displaystylesum_x=1^infty frac1xò)=?$$
sequences-and-series
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, itâÂÂs 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.
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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 $fracpiò6$. As it is incrementally getting closer to $fracpiò6$ I want to see what the delta is to $fracpiò6$ 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?
$$ln(x)-displaystylesum_x=1^infty( fracpiò6 - displaystylesum_x=1^infty frac1xò)=?$$
sequences-and-series
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, itâÂÂs 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.
â 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 $ntoinfty$.
â Did
Aug 10 at 20:06
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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 $fracpiò6$. As it is incrementally getting closer to $fracpiò6$ I want to see what the delta is to $fracpiò6$ 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?
$$ln(x)-displaystylesum_x=1^infty( fracpiò6 - displaystylesum_x=1^infty frac1xò)=?$$
sequences-and-series
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 $fracpiò6$. As it is incrementally getting closer to $fracpiò6$ I want to see what the delta is to $fracpiò6$ 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?
$$ln(x)-displaystylesum_x=1^infty( fracpiò6 - displaystylesum_x=1^infty frac1xò)=?$$
sequences-and-series
edited Aug 10 at 20:07
Did
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asked Aug 10 at 19:55
Joe
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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, itâÂÂs 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, itâÂÂs 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.
â 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 $ntoinfty$.
â Did
Aug 10 at 20:06
add a comment |Â
1
The notation doesn't make much sense...both summations are over the same variable, so the summation is not well defined.
â 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 $ntoinfty$.
â 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.
â 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.
â 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 $ntoinfty$.
â 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 $ntoinfty$.
â Did
Aug 10 at 20:06
add a comment |Â
2 Answers
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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 CesÃÂ ro-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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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
$$-frac263240-gamma +fracpi ^26approx -0.0281149$$
add a comment |Â
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 CesÃÂ ro-Stolz
$$ lim_nto +inftyfraczeta(2)-H_n^(2)frac1n=lim_nto +inftyfracfrac1(n+1)^2frac1n(n+1)=1$$
hence
$$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]=colorredzeta(2)-gamma-1approx 0.0677184.$$
add a comment |Â
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 CesÃÂ ro-Stolz
$$ lim_nto +inftyfraczeta(2)-H_n^(2)frac1n=lim_nto +inftyfracfrac1(n+1)^2frac1n(n+1)=1$$
hence
$$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]=colorredzeta(2)-gamma-1approx 0.0677184.$$
add a comment |Â
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 CesÃÂ ro-Stolz
$$ lim_nto +inftyfraczeta(2)-H_n^(2)frac1n=lim_nto +inftyfracfrac1(n+1)^2frac1n(n+1)=1$$
hence
$$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]=colorredzeta(2)-gamma-1approx 0.0677184.$$
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 CesÃÂ ro-Stolz
$$ lim_nto +inftyfraczeta(2)-H_n^(2)frac1n=lim_nto +inftyfracfrac1(n+1)^2frac1n(n+1)=1$$
hence
$$ lim_nto +inftyleft[log(n)-sum_k=1^nleft(zeta(2)-H_k^(2)right)right]=colorredzeta(2)-gamma-1approx 0.0677184.$$
answered Aug 10 at 20:32
Jack D'Aurizioâ¦
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271k31266632
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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
$$-frac263240-gamma +fracpi ^26approx -0.0281149$$
add a comment |Â
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
$$-frac263240-gamma +fracpi ^26approx -0.0281149$$
add a comment |Â
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
$$-frac263240-gamma +fracpi ^26approx -0.0281149$$
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
$$-frac263240-gamma +fracpi ^26approx -0.0281149$$
answered Aug 11 at 4:59
Claude Leibovici
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112k1055126
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1
The notation doesn't make much sense...both summations are over the same variable, so the summation is not well defined.
â 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 $ntoinfty$.
â Did
Aug 10 at 20:06