On a conjecture of double inequality for the tangent function

In this paper, we prove the conjecture posed by J.-L. Zhao, Q.-M. Luo, B.-N. Guo and F. Qi insert ignore into journalissuearticles values(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]