  In this short note the authors give answers to the three open problems
formulated by Wu and Srivastava [{\it Appl. Math. Lett. 25 (2012),
1347--1353}]. We disprove the Problem 1, by showing that there exists a
triangle which does not satisfies the proposed inequality. We prove the
inequalities conjectured in Problems 2 and 3. Furthermore, we introduce an
optimal refinement of the inequality conjectured on Problem 3.
