The Characterization of the Derivatives for Linear Combinations of Post–Widder Operators inLp Original Research Article

The aim of the paper is to characterize the global rate of approximation of derivativesf(l)through corresponding derivatives of linear combinations of Post–Widder operators in an appropriate weightedLp-metric using a weighted Ditzian and Totik modulus of smoothness, and also to characterize derivatives of these operators in Besov spaces of Ditzian–Totik type.