Abstract:
This paper continues studying of special series with sticking property ($r$-fold coincidence at points $\pm1$) in ultraspherical Jacobi polynomials, that was started in the works of the first author. Investigation of current paper is paid on approximative properties of Vallée-Poussin means for partial sums of mentioned special series with sticking property. It is shown that for function $f$ with certain smoothness properties at the ends of interval $[-1,1]$ the weighted approximation rate by Vallée-Poussin means has the same order as the best weighted approximation of $f$.
Keywords:Jacobi polynomials, special (sticking) series of ultraspherical polynomials, approximation properties, weighted approximation, Vallée-Poussin means.