Asymptotic expansions for the generalised trigonometric integral and its zeros

Fuente: arXiv
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Main Author: Nemes, Gergő
Format: Preprint
Published: 2024
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author Nemes, Gergő
author_facet Nemes, Gergő
contents In this paper, we investigate the asymptotic properties of the generalised trigonometric integral $\operatorname{ti}(a, z, α)$ and its associated modulus and phase functions for large complex values of $z$. We derive asymptotic expansions for these functions, accompanied by explicit and computable error bounds. For real values of $a$, the function $\operatorname{ti}(a, z, α)$ possesses infinitely many positive real zeros. Assuming $a < 1$, we establish asymptotic expansions for the large zeros, accompanied by precise error estimates. The error bounds for the asymptotics of the phase function and its zeros will be derived by studying the analytic properties of both the phase function and its inverse. Additionally, we demonstrate that for real variables, the derived asymptotic expansions are enveloping, meaning that successive partial sums provide upper and lower bounds for the corresponding functions.
format Preprint
id arxiv_https___arxiv_org_abs_2412_19174
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Asymptotic expansions for the generalised trigonometric integral and its zeros
Nemes, Gergő
Classical Analysis and ODEs
41A60, 33B99
In this paper, we investigate the asymptotic properties of the generalised trigonometric integral $\operatorname{ti}(a, z, α)$ and its associated modulus and phase functions for large complex values of $z$. We derive asymptotic expansions for these functions, accompanied by explicit and computable error bounds. For real values of $a$, the function $\operatorname{ti}(a, z, α)$ possesses infinitely many positive real zeros. Assuming $a < 1$, we establish asymptotic expansions for the large zeros, accompanied by precise error estimates. The error bounds for the asymptotics of the phase function and its zeros will be derived by studying the analytic properties of both the phase function and its inverse. Additionally, we demonstrate that for real variables, the derived asymptotic expansions are enveloping, meaning that successive partial sums provide upper and lower bounds for the corresponding functions.
title Asymptotic expansions for the generalised trigonometric integral and its zeros
topic Classical Analysis and ODEs
41A60, 33B99
url https://arxiv.org/abs/2412.19174