A proof that Euler missed: Evaluating \(\zeta\) (2) the easy way
The author proves Euler's identity \(\sum^{\infty}_{n=1}n^{- 2}=\pi^ 2/6\) by simply evaluating a certain double integral in two different ways. Contrary to the more standard proofs this approach can be presented in a course in elementary calculus.
scientific article; zbMATH DE number 3855198