“混合型”雅可比级数的泰勒平均的点态逼近

THE POINTWISE APPROXIMATION BY THE TAYLOR MEANS OF IIMIXED"JACOBI SERIE-S

给出了用“混合型”雅可比级数的泰勒平均逼近黎普希兹函数类的点态估计．

It is given that pointwise estimates of approximation to functions in the class lipα(0≤α<1)by the Taylor means of the'mixed' Jacobi series. BY P (x)denote the Jacobi polinomials and by (x)denote the Taylor means of the series (f)p(x). Suppose f(x) ∈lipα(0≤α< 1, - 1≤x≤1),then when -1<x<1, we have