混合型Jacobi级数的［F，d_n］平均的点态逼近

THE POINTWISE APPROXIMATION BY THE [F,d_n]MEANS OF MIXED JACOBI SERIES

用混合型Ｊａｃｏｂｉ级数的部分和的［Ｆ，ｄｎ］平均逼近ｌｉｐａ类函数，给出了相应的点态估计．

Let (x) be Jacobi polynomial. By (f;x) denote the [F,dn] means of thepartial sums (f;x) of Jacobi series,that is,where Pn,k are defined by the relation:In this paper the following results are given.If f(x) ∈lipα (0<α<1 - 1≤x≤1 ),then for |x | <1,we havewhere