Bourlet's Theorem for the product of differential operators, an application of the operator method and a proof for $\sum_{n=1}^{\infty}\frac{1}{n^2}=\frac{π^2}{6}$, that Euler missed, derived from difference equations

paper

Bourlet's Theorem for the product of differential operators, an application of the operator method and a proof for $\sum_{n = 1}^{\infty} \frac{1}{n ^{2}} = \frac{π ^{2}}{6}$ , that Euler missed, derived from difference equations

arXiv:1506.06241

We give another proof for \[ \sum_{n=1}^{\infty}\frac{1}{n^2}=\frac{π^2}{6} \] that basically follows from the theory of difference equations.

9 pages