# An Elementary Proof for Euler's Series

### Daniel J. Velleman Am Math Monthly, V 123, N 1, Jan 2016, p. 77

In an earlier note, Yoshio Matsuoka gave an elementary proof for the sum of Euler's series, $\displaystyle\sum_{i=1}^{\infty}\frac{1}{n^2}=\frac{\pi^2}{6}.\;$ Below we sketch a simplified version of Matsuoka's proof.