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An integral hidden in Gradshteyn and Ryzhik. (English) Zbl 0939.33007

The authors provide a closed-form expression for the integral \[ \begin{aligned} N_{0,4}(a;m) & := \int^\infty_0 {dz\over (z^4+ 2az^2+ 1)^{m+1}},\quad \text{where }m\in \mathbb{N}\text{ and }a\in (-1,\infty):\\N_{0,4}(a;m) &= {\pi\over 2^{m+{3\over 2}}(a+ 1)^{m+{1\over 2}}} P^{(m+{1\over 2},-m-{1\over 2})}(a)\\ & = {\pi\over 2^{3m+{3\over 2}}(a+ 1)^{m+{1\over 2}}} \sum^m_{k= 0} 2^k {2m-2k\choose m-k}{m+k\choose m}(a+ 1)^k.\end{aligned} \] They have given the CPU table of \(N_{0,4}(4,m)\) by comparing CPU times of the direct calculation with the CPU time of their formula. There is a significance difference.
Reviewer: R.S.Dahiya (Ames)

MSC:

33C45 Orthogonal polynomials and functions of hypergeometric type (Jacobi, Laguerre, Hermite, Askey scheme, etc.)
Full Text: DOI

References:

[1] G. Boros, V. Moll, Landen Transformations and the Integration of Rational Functions, preprint.; G. Boros, V. Moll, Landen Transformations and the Integration of Rational Functions, preprint. · Zbl 0988.33009
[2] Gradshteyn, I. S.; Ryzhik, I. M., (Jeffrey, A., Table of Integrals, Series and Products (1994), Academic Press: Academic Press New York) · Zbl 0918.65002
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