International Journal of Mathematics and Mathematical Sciences
Volume 2006 (2006), Article ID 76782, 6 pages

An identity related to Jordan's inequality

Jian-Lin Li

College of Mathematics and Information Science, Shaanxi Normal University, Xi'an 710062, China

Received 28 July 2006; Revised 29 September 2006; Accepted 2 October 2006

Copyright © 2006 Jian-Lin Li. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The main purpose of this note is to establish an identity which states that the function sinx/x is a power series of (π24x2) with positive coefficients for all x0. This enable us to obtain a much stronger Jordan's inequality than that obtained before.