关于Techebycheff-Fourier级数的(N,σ)平均逼近

On the Approximation by (N,σ) Means of Techebycheff-Fourier Series

本文定义了（N，σ）求和法，讨论函数人f（x）∈r[-1，1]，（r∈N）的切彼晓夫-富里埃级数的逼近阶．

The summability of (N,d) is defined, the degree of approximation to a function f(x)∈r[- 1, 1] (r∈N9) by (N,σ) means of its Techebycheff-Fourier series is discussed.