# Simple Proofs for $$\sum_{k=1}^{\infty} \frac{1}{k^2} = \frac{π^2}{6}$$ and $$\sin x = x \prod_{k=1}^{\infty}(1 - \frac{x^2}{k^2\pi^2})$$

by R. A. Kortram

Mathematics Magazine
April, 1996

Subject classification(s): Single Variable Calculus | Series
Applicable Course(s): 4.11 Advanced Calc I, II, & Real Analysis

Two of Euler's familiar identities, the sum of reciprocals of squares of integers and the infinite product expression of sine function, are proved again.

A pdf copy of the article can be viewed by clicking below. Since the copy is a faithful reproduction of the actual journal pages, the article may not begin at the top of the first page.