Chebyshev series expansion of inverse polynomials
Abstract
The Chebyshev series expansion of the inverse of a polynomial is well defined if the polynomial has no roots in [-1,1]. If the inverse polynomial is decomposed into partial fractions, the an are linear combinations of simple functions of the polynomial roots. Also, if the first k of the coefficients an are known, the others become linear combinations of these derived recursively from the bj's. On a closely related theme, finding a polynomial with minimum relative error towards a given f(x) is approximately equivalent to finding the bj in ; a Newton algorithm produces these if the Chebyshev expansion of f(x) is known.
- Publication:
-
Journal of Computational and Applied Mathematics
- Pub Date:
- November 2006
- DOI:
- 10.1016/j.cam.2005.10.013
- arXiv:
- arXiv:math/0403344
- Bibcode:
- 2006JCoAM.196..596M
- Keywords:
-
- Chebyshev series;
- Orthogonal polynomials;
- Approximation;
- Mathematics - Classical Analysis and ODEs;
- 33C45 (Primary);
- 42C20;
- 41A50 (Secondary)
- E-Print:
- LaTeX2e, 24 pages, 1 PostScript figure. More references. Corrected typos in (1.1), (3.4), (4.2), (A.5), (E.8) and (E.11)