Spherical Laws of Sines and Cosines/Mistake

Source Work

 * Chapter $5$: Eternal Triangles: Trigonometry and logarithms
 * Early trigonometry
 * 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, ] 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 and was actually published in $1464$.

Also see

 * Law of Sines for Spherical Triangles
 * Law of Cosines for Spherical Triangles