International Journal of Mathematics and Mathematical Sciences
Volume 2006 (2006), Article ID 76782, 6 pages
doi:10.1155/IJMMS/2006/76782
An identity related to Jordan's inequality
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.
Abstract
The main purpose of this note is to establish an
identity which states that the function sinx/x is a power series of (π2−4x2) with positive coefficients for all x≠0. This enable us to obtain a much stronger Jordan's inequality
than that obtained before.