Basel problem


The Basel problemMathworldPlanetmath, first posed by Pietro Mengoli in 1644, asks for a finite formula for the infinite sum

i=11i2.

Though Mengoli verified the Wallis formulae for π, it did not occur to him that π was also involved in the solution of this problem. Jakob Bernoulli also tried in vain to solve this problem. Even an approximate decimal value eluded contemporary mathematicians: an answer accurate to just five decimal places requires iterating up to at least i=112000, which without the aid of a computer was wholly impractical in Mengoli’s day. The problem was finally solved in 1741, when, after almost a decade of work, Leonhard Euler conclusively proved that

π26=ζ(2)=i=11i2.

The value, 1.6449340668482264365… could then be computed to almost as many decimal places as were known of π. See value of the Riemann zeta functionDlmfDlmfMathworldPlanetmath at s=2 (http://planetmath.org/ValueOfTheRiemannZetaFunctionAtS2)

References

  • 1 Ed Sandifer, “Euler’s Solution of the Basel Problem - The Longer Story”. Danbury, Connecticut: Western Connecticut State University (2003)
Title Basel problem
Canonical name BaselProblem
Date of creation 2013-03-22 18:05:22
Last modified on 2013-03-22 18:05:22
Owner PrimeFan (13766)
Last modified by PrimeFan (13766)
Numerical id 5
Author PrimeFan (13766)
Entry type Definition
Classification msc 11A25