On the degree of approximation of certain continuous bivariate functions by double matrix means of a double Fourier series

Document Type : Research Paper

Author

Department of Mathematics and Informatics, University of Prishtina "Hasan Prishtina", Prishtina, Kosovo

Abstract

In this paper, we have studied the degree of approximation of certain bivariate functions by double factorable matrix means of a double Fourier series. Four theorems are proved using single rest bounded variation sequences, single head bounded variation sequences, double rest bounded variation sequences, and two non-negative mediate functions. These results expressed in terms of two functions of modulus type and two non-negative mediate functions, imply many particular results as shown at last section of this paper.

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