ON TRIGONOMETRICALLY QUASI-CONVEX FUNCTIONS

In this paper, we introduce and study the concept of trigono- metrically quasi-convex function. We prove Hermite-Hadamard type in- equalities for the newly introduced class of functions and obtain some new Hermite-Hadamard inequalities for functions whose rst derivative in absolute value, raised to a certain power which is greater than one, respectively at least one, is trigonometrically quasi-convex convex. We also extend our initial results to functions of several variables. Next, we point out some applications of our results to give estimates for the ap- proximation error of the integral the function in the trapezoidal formula. KCI Citation Count: 0