English

Fibonacci--Theodorus Spiral and its properties

General Mathematics 2024-09-10 v2

Abstract

Inspired by the ancient spiral constructed by the greek philosopher Theodorus which is based on concatenated right triangles, we have created a spiral. In this spiral, called \emph{Fibonacci--Theodorus}, the sides of the triangles have lengths corresponding to Fibonacci numbers. Towards the end of the paper, we present a generalized method applicable to second-order recurrence relations. Our exploration of the Fibonacci--Theodorus spiral aims to address a variety of questions, showcasing its unique properties and behaviors. For example, we study topics such as area, perimeter, and angles. Notably, we establish a relationship between the ratio of two consecutive areas and the golden ratio, a pattern that extends to angles sharing a common vertex. Furthermore, we present some asymptotic results. For instance, we demonstrate that the sum of the first nn areas comprising the spiral approaches a multiple of the sum of the initial nn Fibonacci numbers. Moreover, we provide a sequence of open problems related to all spiral worked in this paper. Finally, in his work Hahn, Hahn observed a potential connection between the golden ratio and the ratio of areas between spines of lengths Fn+1\sqrt{F_{n+1}} and Fn+21\sqrt{F_{n+2}-1} and the areas between spines of lengths Fn\sqrt{F_{n}} and Fn+11\sqrt{F_{n+1}-1} in the Theodorus spiral. However, no formal proof has been provided in his work. In this paper, we provide a proof for Hahn's conjecture.

Cite

@article{arxiv.2407.07109,
  title  = {Fibonacci--Theodorus Spiral and its properties},
  author = {Michael R. Bacon and Charles K. Cook and Rigoberto Flórez and Robinson A. Higuita and Florian Luca and José L. Ramírez},
  journal= {arXiv preprint arXiv:2407.07109},
  year   = {2024}
}

Comments

Accepted for publication by Proceedings of Fibonacci Quarterly

R2 v1 2026-06-28T17:34:46.370Z