Let , on ,
By using the Taylor’s formula, the author proves that for each the following inequalities
hold. These inequalities generalize some inequalities of K. S. K. Iyengar [Math. Student 6, 75-76 (1938)], P. M. Vasić and G. V. Milovanović [Publ. Fac. Electrotechn. Univ. Belgrade, Ser. Math. Phys. 544-576, 18-24 (1977; Zbl 0351.26019)] and G. V. Milovanović and J. E. Pečarić [Publ. Fac. Eletrotechn. Univ. Belgrade, Ser. Math. Phys. 544-576, 166-170 (1976; Zbl 0346.26017)].