Abstract
We estimate the order of weighted approximations of functions and their derivatives by using the means of mixed series of Legendre polynomials. As the main result, we obtain estimates of the order of approximation of a function and its derivatives by the Vallé-Poussin means and their derivatives.
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I. I. Sharapudinov, “Approximation of functions of variable smoothness by Fourier-Legendre sums,” Mat. Sb. 191(5), 143–160 (2000) [Russian Acad. Sci. Sb. Math. 191 (5), 759–777 (2000)].
I. I. Sharapudinov, “The mixed series by Улътрасферическим the polynomials and them the approximation properties,” Mat. Sb. 194(3), 115–148 (2003) [Russian Acad. Sci. Sb. Math. 194 (3), 423–456 (2003)].
I. I. Sharapudinov, “Approximation properties of the operators \( Y \) n+2r (f) and of their discrete analogs,” Mat. Zametki 72(5), 765–795 (2002) [Math. Notes 72 (5), 705–732 (2002)].
I. I. Sharapudinov, Mixed Series of Orthogonal Polynomials: Theory and Applications (DNTs RAN, Makhachkala, 2004) [in Russian].
I. I. Sharapudinov, “Approximation properties of mixed series in terms of Legendre polynomials on the classes W r,” Mat. Sb. 197(3), 135–154 (2006) [Russian Acad. Sci. Sb. Math. 197 (3), 433–452 (2006)].
S. A. Telyakovskii, “Two theorems on approximation of functions by algebraic polynomials,” Mat. Sb. 70(2), 252–265 (1966).
I. Z. Gopengauz, “A theorem of A. F. Timan on the approximation of functions by polynomials on a finite interval,” Mat. Zametki the papers 1(2), 163–172 (1967).
G. Szegö, Orthogonal Polynomials, Colloquium Publ. (Amer. Math. Soc., Providence, RI, 1959; Fizmatgiz, Moscow, 1962), Vol. XXIII.
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Original Russian Text © I. I. Sharapudinov, 2008, published in Matematicheskie Zametki, 2008, Vol. 84, No. 3, pp. 452–471.
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Sharapudinov, I.I. Approximation properties of the Vallée-Poussin means of partial sums of a mixed series of Legendre polynomials. Math Notes 84, 417–434 (2008). https://doi.org/10.1134/S0001434608090125
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DOI: https://doi.org/10.1134/S0001434608090125