Fejer算子逼近导数有界变差的函数

On the Approximation of Fejer Operators for Functions with Derivatives of Bounded Variation

本文给出Fej(?)算子对导数为有界变差函数的逼近速度的估计。

In this paper, we give the rate of the convergence of the Fejer operators for the functions with derivatives of bounded variation, we obtain the following theorem: let f∈c_(2(?)), f'∈BV[-π, π], then we have for n(?)3 |δn(f; x)-f(x)|≤ 6lnn/n|φ(x+o)-φ(x-o)| where φ(x)=f'(x) and