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Bibliographic Details
Main Author: Ducharme, Andrew
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2405.19371
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author Ducharme, Andrew
author_facet Ducharme, Andrew
contents Special functions like the polygamma, Hurwitz zeta, and Lerch zeta functions have sporadically been connected with the nth derivatives of trigonometric functions. We show the polylogarithm $\text{Li}_s(z)$, a function of complex argument and order $z$ and $s$, encodes the nth derivatives of the cotangent, tangent, cosecant and secant functions, and their hyperbolic equivalents, at negative integer orders $s = -n$. We then show how at the same orders, the polylogarithm represents the nth application of the operator $x \frac{d}{dx}$ on the inverse trigonometric and hyperbolic functions. Finally, we construct a sum relating two polylogarithms of order $-n$ to a linear combination of polylogarithms of orders $s = 0, -1, -2, ..., -n$.
format Preprint
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institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Unifying trigonometric and hyperbolic function derivatives via negative integer order polylogarithms
Ducharme, Andrew
General Mathematics
33B10, 33E20, 26A06, 11G55
Special functions like the polygamma, Hurwitz zeta, and Lerch zeta functions have sporadically been connected with the nth derivatives of trigonometric functions. We show the polylogarithm $\text{Li}_s(z)$, a function of complex argument and order $z$ and $s$, encodes the nth derivatives of the cotangent, tangent, cosecant and secant functions, and their hyperbolic equivalents, at negative integer orders $s = -n$. We then show how at the same orders, the polylogarithm represents the nth application of the operator $x \frac{d}{dx}$ on the inverse trigonometric and hyperbolic functions. Finally, we construct a sum relating two polylogarithms of order $-n$ to a linear combination of polylogarithms of orders $s = 0, -1, -2, ..., -n$.
title Unifying trigonometric and hyperbolic function derivatives via negative integer order polylogarithms
topic General Mathematics
33B10, 33E20, 26A06, 11G55
url https://arxiv.org/abs/2405.19371