Basel problem

Euler's 1734 answer to a question open for almost a century. History: posed 1650, solved 1734.

\sum_{k=1}^{\infty} \frac{1}{k^2} = \frac{\pi^2}{6}

How to work it out

1
The statement:
$\sum_{k=1}^{\infty} \frac{1}{k^2} = \frac{\pi^2}{6}$
2
Euler's 1734 answer to a question open for almost a century.
3
Below, the numbers in the table are computed by this site from the definition, not copied.

LaTeX source of the formulas on this page

\[ \sum_{k=1}^{\infty} \frac{1}{k^2} = \frac{\pi^2}{6} \]

What is the basel problem?

Euler's 1734 answer to a question open for almost a century.

Who is the Basel problem associated with?

Leonhard Euler, Jacob Bernoulli.