Comment on "An algebra and trigonometry-based proof of Kepler's first law" by Akarsh Simha, arXiv:2111.08447v1

TL;DR

This paper comments on a recent non-calculus proof of Kepler's first law, highlighting an obscure but valid property of the ellipse that underpins the proof.

Contribution

It provides a critical analysis of the algebra and trigonometry-based proof, clarifying the elliptical property involved.

Findings

Identifies the key elliptical property used in the proof

Clarifies the validity of the property in the proof

Highlights the importance of geometric properties in orbital laws

Abstract

The recent non-calculus proof of Kepler's first law succeeds because of an obscure, but valid property of the ellipse.