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http://dx.doi.org/10.5666/KMJ.2012.52.3.347

Partial Fraction Expansions for Newton's and Halley's Iterations for Square Roots  

Kouba, Omran (Department of Mathematics, Higher Institute for Applied Sciences and Technology)
Publication Information
Kyungpook Mathematical Journal / v.52, no.3, 2012 , pp. 347-357 More about this Journal
Abstract
When Newton's method, or Halley's method is used to approximate the pth root of 1-z, a sequence of rational functions is obtained. In this paper, a beautiful formula for these rational functions is proved in the square root case, using an interesting link to Chebyshev's polynomials. It allows the determination of the sign of the coefficients of the power series expansion of these rational functions. This answers positively the square root case of a proposed conjecture by Guo(2010).
Keywords
Newton's method; Halley's method; Series expansion; Square roots; Chebyshev's Polynomials;
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  • Reference
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