Abstract

The main purpose of this paper is to present two methods of sharpening Jordan's inequality. The first method shows that one can obtain new strengthened Jordan's inequalities from old ones. The other method shows that one can sharpen Jordan's inequality by choosing proper functions in the monotone form of L'Hopital's rule. Finally, we improve a related inequality proposed early by Redheffer.

Highlights

  • The well-known Jordan’s inequality states that sin x/x ≥ 2/π (x ∈ (0,π/2]) holds with equality if and only if x = π/2. It plays an important role in many areas of pure and applied mathematics

  • In a recent paper [10], the first author established an identity which states that the function sin x/x is a power series of (π2 − 4x2) with positive coefficients for all x = 0

  • Motivated by the previous research on Jordan’s inequality, in this paper, we present two methods of sharpening Jordan’s inequality

Read more

Summary

Introduction

The well-known Jordan’s inequality states that sin x/x ≥ 2/π (x ∈ (0,π/2]) holds with equality if and only if x = π/2 (see [1]). It plays an important role in many areas of pure and applied mathematics. This inequality was first extended to the following: sin x x. It was further extended to the following:. Which holds with equality if and only if x = π/2 (see [2,3,4]). The monotone form of L’Hopital’s rule (see [5, Lemma 5.1]) has been successfully used by Zhu [6, 7] and Wu and Debnath [8, 9] to sharpen

Journal of Inequalities and Applications
New inequalities from old ones
Sharpening Jordan’s inequality
A related inequality

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.