What is the proof for the value of the Riemann Zeta Function at 2?

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Discussion Overview

The discussion centers around the proof of the value of the Riemann Zeta Function at 2, specifically the equation \(\zeta(2) = \frac{\pi^2}{6}\). Participants explore various methods of proof, including references to Fourier analysis and historical approaches by mathematicians such as Euler. The scope includes theoretical insights and references to mathematical literature.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant expresses intrigue about the relationship between the geometric series and the value of \(\zeta(2)\), seeking an accessible explanation.
  • Another participant mentions an elementary proof found on Wikipedia but expresses skepticism about the existence of an easy proof.
  • A participant suggests that Euler's precalculus book contains computations of the series and relates even values of the zeta function to Bernoulli numbers using Fourier series.
  • Links to various resources are provided, including a document offering multiple evaluations of \(\zeta(2)\) and a guide through Euler's original derivation.
  • Fourier series methods are noted as providing shorter and more generalizable proofs, with references to additional threads on the topic.
  • A mention of an elementary paper by Xuming Chen discussing recursive formulas for \(\zeta(2k)\) and \(L(2k - 1)\) is included.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the existence of an easy proof for \(\zeta(2)\), with some expressing doubt and others providing resources that suggest various methods of proof. The discussion remains unresolved regarding the accessibility of these proofs.

Contextual Notes

Some participants reference specific mathematical literature and proofs that may depend on prior knowledge of Fourier analysis and advanced calculus concepts. The discussion includes links to external resources that may contain varying levels of rigor and accessibility.

imranq
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So we were going over geometric series in my calc class (basic, I know), however I was intrigued by one point that the prof. made during lecture

[tex]\frac{\pi^2}{6} = \sum^{\infty}_{n=1}\frac{1}{n^2} = \zeta (2)[/tex]

That's amazing (at least to me). Looking for the explanation for this, I found a bunch of stuff relating to Fourier analysis which was - unfortunately - written in vague terms. Would someone explain this proof that is accessible to a Calc II student? Thanks
 
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That was fast and I understand it now, thanks! By the way, what is the Fourier series used for?
 
Last edited:
you might enjoy the computation in euler's precalculus book of this series. he also did it for many other values of zeta, and apparently gave a general formula relating all even values of zeta to the bernoulli numbers, as given in the appendix to milnor and stasheff, characteristic classes, using Fourier series.
 
http://www.maths.ex.ac.uk/~rjc/etc/zeta2.pdf
Gives 14 different evaluations (its also linked on the wikipedia page incidentally).

The part on zeta function values at http://www.ams.org/bull/2007-44-04/S0273-0979-07-01175-5/S0273-0979-07-01175-5.pdf, guides you through Euler's original derivation (which is easily made rigorous once the infinite product for the sine is obtained).

Fourier series methods offer shorter and easily generalised proofs, for instance, check the following threads,

https://www.physicsforums.com/showthread.php?t=192765
and
https://www.physicsforums.com/showthread.php?t=95994

There was also an elementary paper by Xuming Chen in the College Mathematics Journal called 'Recursive Formulas for [itex]\zeta(2k)[/tex] and [itex]L(2k - 1)[/tex]'.<br /> <br /> Hope this helped![/itex][/itex]
 
Last edited by a moderator:
yasiru89 said:
http://www.maths.ex.ac.uk/~rjc/etc/zeta2.pdf
Gives 14 different evaluations (its also linked on the wikipedia page incidentally).

The part on zeta function values at http://www.ams.org/bull/2007-44-04/S0273-0979-07-01175-5/S0273-0979-07-01175-5.pdf, guides you through Euler's original derivation (which is easily made rigorous once the infinite product for the sine is obtained).

Fourier series methods offer shorter and easily generalised proofs, for instance, check the following threads,

https://www.physicsforums.com/showthread.php?t=192765
and
https://www.physicsforums.com/showthread.php?t=95994

There was also an elementary paper by Xuming Chen in the College Mathematics Journal called 'Recursive Formulas for [itex]\zeta(2k)[/tex] and [itex]L(2k - 1)[/tex]'.<br /> <br /> Hope this helped![/itex][/itex]
[itex][itex] <br /> Thanks a lot![/itex][/itex]
 
Last edited by a moderator:

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