On Some Bullen-type Inequalities with the kth Power for Twice Differentiable Mappings and Applications

We present the generalization of power-mean inequality. Further, we establish some Bullen-type inequalities with the kth power for twice differentiable mappings via s-convex functions in the first and second sense and s-concave functions. Some applications to special means of real numbers and to polygamma functions are also given.