Expression of Farhi's integral in terms of known mathematical constants

Fuente: arXiv
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Autore principale: Pain, Jean-Christophe
Natura: Preprint
Pubblicazione: 2024
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author Pain, Jean-Christophe
author_facet Pain, Jean-Christophe
contents In an interesting article entitled "A curious formula related to the Euler Gamma function", Bakir Farhi posed the open question of whether it was possible to obtain an expression of $$ \boldsymbolη=2\int_0^1\logΓ(x)\,\cdot\sin(2πx)\,\mathrm{d}x=0.7687478924\dots $$ in terms of the known mathematical constants as $π$, $\logπ$, $\log 2$, $Γ(1/4)$, $e$, etc. In the present work, we show that $$ \boldsymbolη=\frac{1}π\left[γ+\log(2π)\right], $$ where $γ$ is the usual Euler-Mascheroni constant, and provide two different proofs, the first one involving the Glaisher-Kinkelin constant, and the second one based on the Malmstén integral representation of $\logΓ(x)$. The resulting formula can also be obtained directly from the knowledge of the Fourier series expansion of $\logΓ(x)$.
format Preprint
id arxiv_https___arxiv_org_abs_2408_14835
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Expression of Farhi's integral in terms of known mathematical constants
Pain, Jean-Christophe
Number Theory
In an interesting article entitled "A curious formula related to the Euler Gamma function", Bakir Farhi posed the open question of whether it was possible to obtain an expression of $$ \boldsymbolη=2\int_0^1\logΓ(x)\,\cdot\sin(2πx)\,\mathrm{d}x=0.7687478924\dots $$ in terms of the known mathematical constants as $π$, $\logπ$, $\log 2$, $Γ(1/4)$, $e$, etc. In the present work, we show that $$ \boldsymbolη=\frac{1}π\left[γ+\log(2π)\right], $$ where $γ$ is the usual Euler-Mascheroni constant, and provide two different proofs, the first one involving the Glaisher-Kinkelin constant, and the second one based on the Malmstén integral representation of $\logΓ(x)$. The resulting formula can also be obtained directly from the knowledge of the Fourier series expansion of $\logΓ(x)$.
title Expression of Farhi's integral in terms of known mathematical constants
topic Number Theory
url https://arxiv.org/abs/2408.14835