### MathFoundations27: Trigonometry with rational numbers

Rational trigonometry works over the rational numbers, and allows us a more elementary and logical approach to the basics of trigonometry. This video illustrates the Spread law, the Cross law and the Triple spread formula. These are among the most important formulas in geometry, indeed in all of mathematics, and they allow us to recast trigonometry into a simpler and more computationally elegant subject. See the WildTrig YouTube series for lots of applications of these laws.This lecture is part of the MathFoundations series, which tries to lay out proper foundations for mathematics, and will not shy away from discussing the serious logical difficulties entwined in modern pure mathematics. The full playlist is at http://www.youtube.com/playlist?list=PL5A714C94D40392AB&feature=view_all

Length:
09:34