On a conjecture of double inequality for the tangent function

Year 2016, Volume: 45 Issue: 1, 43 - 48, 01.02.2016

Mansour Mahmoud

Abstract

In this paper, we prove the conjecture posed by J.-L. Zhao, Q.-M. Luo,
B.-N. Guo and F. Qi (Remarks on inequalities for the tangent function,
Hacettepe J. Math. Stat., 41, no. 4, 499-506, 2012) about a sharp double inequality of the tangent function, which is a generalization of the
Becker-Stark inequality. Also, the new double inequality is compared
with the double inequality presented in [3] 

Keywords

Tangent function, L’Hôpital’s rule, inequality, best constants, Concavity

References

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