Approximation of Unbounded Functions by Trigonometric Polynomials

Abstract

The purpose of this paper is present a brief survey of know on estimates the rate for best approximation of unbounded functions by suitable trigonometric polynomials of one variable in weighted space L_(p,α) (X). Moreover we studied concerning the degree of best trigonometric approximation of f^((k)) with k non-integer in L_(p,α) (X).