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arXiv · 2111.08447

An algebra and trigonometry -based proof of Kepler's First Law

Akarsh Simha
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Abstract

An elementary proof of Kepler's first law, i.e. that bounded planetary orbits are elliptical, is derived without the use of calculus. The proof is similar in spirit to previous derivations, in that conservation laws are used to obtain an expression for the planetary orbit, which is then compared against an equation for the ellipse. However, we derive the equation that we match against, using trigonometry, from two well-known properties of the ellipse. Calculus is avoided altogether.

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Akarsh Simha. 2021-11-05. An algebra and trigonometry -based proof of Kepler's First Law. https://doi.org/10.1119/10.0005669

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