# Spherical Laws of Sines and Cosines/Mistake

## Source Work

Chapter $5$: Eternal Triangles: Trigonometry and logarithms
Early trigonometry

This mistake can be seen in the $2008$ edition as published by Quercus: ISBN 978-1-84724-768-1

## Mistake

"He [that is, Georg Joachim Rhaeticus] stated the law of sines for spherical triangles ... and the law of cosines ... in his De Triangulis, written in 1462-3 but not published until 1533."

The book De Triangulis (Omnimodus) was in fact by Johannes Müller von Königsberg ("Regiomontanus") and was actually published in $1464$.