An algebraic framework for rational trigonometry (II) | WildTrig: Intro to Rational Trigonometry

The most powerful law in geometry is the Cross law, the rational analog of the Cosine law. It includes as special cases Pythagoras' theorem and the Triple quad formula. Here we sketch a purely algebraic derivation of the Cross law, and then how the other four main laws of rational trigonometry follow from it.

This video is part of the WildTrig series, which introduces Rational Trigonometry and applies it to many different aspects of geometry.

Video Contents:
00:00 Intro to Rational Trigonometry
2:56 Spread and cross between lines
6:21 Cross law
8:10 Spread law
8:39 Triple spread formula

************************

Here are the Insights into Mathematics Playlists:

Here are the Wild Egg Maths Playlists (some available only to Members!)

************************