English

What do sin$(x)$ and arcsinh$(x)$ have in Common?

Classical Analysis and ODEs 2024-11-05 v1 Discrete Mathematics Combinatorics

Abstract

N. G. de Bruijn (1958) studied the asymptotic expansion of iterates of sin(x)(x) with 0<xπ/20 < x \leq \pi/2. Bencherif & Robin (1994) generalized this result to increasing analytic functions f(x)f(x) with an attractive fixed point at 0 and x>0x > 0 suitably small. Mavecha & Laohakosol (2013) formulated an algorithm for explicitly deriving required parameters. We review their method, testing it initally on the logistic function (x)\ell(x), a certain radical function r(x)r(x), and later on several transcendental functions. Along the way, we show how (x)\ell(x) and r(x)r(x) are kindred functions; the same is also true for sin(x)(x) and arcsinh(x)(x).

Cite

@article{arxiv.2411.01591,
  title  = {What do sin$(x)$ and arcsinh$(x)$ have in Common?},
  author = {Steven Finch},
  journal= {arXiv preprint arXiv:2411.01591},
  year   = {2024}
}

Comments

24 pages

R2 v1 2026-06-28T19:46:31.930Z