Using the family of generalized Baskakov operators we propose a general method to construct positive linear preserving exponential functions. A conjecture concerning Voronovskaja type formula and some applications are presented.

There are presented two methods for approximation of generalized Urysohn type operators. The first them is the natural generalization method considered by Demkiv in [1]. convergence results given quantitative form, using certain moduli continuity. In final part there a few exemplifications discrete and integral operators and, particular, Bernstein Durrmeyer

In the present paper we give quantitative type theorems for differences of different bivariate positive linear operators by using weighted modulus continuity. Similar estimates are obtained via K-functional and Chebyshev functionals. Moreover, an example involving Szasz Szasz-Kantorovich is given.