A method to obtain the best uniform polynomial approximation for the family of rational function

Iranian Journal of Optimization

مقاله 1، دوره 7، شماره 1، شهریور 2015، صفحه 753-766   

نوع مقاله: Research Paper

نویسندگان

M. A. Fariborzi Araghi^{* 1}؛ F. Froozanfar²

¹Department of Mathematics, Islamic Azad university, Central Tehran branch

²Ms.student of Mathematics, Islamic Azad university, Kermanshah branch, Kermanshah, Iran

چکیده

In this article, by using Chebyshev’s polynomials and Chebyshev’s expansion, we obtain the best uniform polynomial approximation out of P_2n to a class of rational functions of the form (ax²+c)^-1 on any non symmetric interval [d,e]. Using the obtained approximation, we provide the best uniform polynomial approximation to a class of rational functions of the form (ax²+bx+c)^-1 for both cases b²-4ac L 0 and b²-4ac G 0. 
 

کلیدواژه‌ها

Chebyshev’s polynomials؛ Chebyshev’s expansion؛ uniform norm؛ the best uniform polynomial approximation؛ alternating set

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