Cent. Eur. J. Math. • 6(2) • 2008 • 325-334 DOI: 10.2478/s11533-008-0025-9 Central European Journal of Mathematics Convergence and Voronovskaja-type theorems for derivatives of generalized Baskakov operators Research Article Abdul Wafi ∗ , Salma Khatoon † Department Of Mathematics, Faculty of Natural Sciences, Jamia Millia Islamia, New Delhi-110025, India Received 27 November 2007; accepted 5 March 2008 Abstract: In the present paper our aim is to establish convergence and Voronovskaja-type theorems for first derivatives of generalized Baskakov operators for functions of one and two variables in exponential and polynomial weight spaces. MSC: 41A36, 41A63 Keywords: exponential weight spaces • derivatives of linear positive operators • convergence and Voronovskaja-type theorems © Versita Warsaw and Springer-Verlag Berlin Heidelberg. 1. Introduction Becker [1, 2] examined the Szász-Mirakjan and Baskakov operators for functions of one variable in polynomial and exponential weight spaces. Corresponding generalized Baskakov operators for functions of one variable were also studied in polyomial and exponential weight spaces by us in [10, 11]. Recently, many papers were published on approximation by modified Szász-Mirakjan and Baskakov operators for func- tions of one and two variables [3, 4, 6, 7, 12] which deals with convergence, degree of approximation, and Voronovskaja- type theorems as well as convergence of partial derivatives of these operators. In [9] we introduced generalized Baskakov operators for functions of two variables in polynomial and exponential weight spaces. We also investigated the degree of approximation for functions of one and two variables and obtained the convergence and direct theorems. In the present paper we study the convergence of first derivatives of generalized Baskakov operators for functions of one and two variables with polynomial and exponential growth and also obtain a Voronovskaja-type theorem. ∗ E-mail: abdulwafi2002@yahoo.co.in † E-mail: sk_hareem@hotmail.com 325