Pythagasaurus is the fabled Tyrannosaurus practiced in the skills of trigonometry and long division. Apparently he knows all eight numbers. [Via]
posted by homunculus on Nov 11, 2011 - 9 comments

Trigonometric Delights. This book is neither a textbook of trigonometry—of which there are many—nor a comprehensive history of the subject, of which there is almost none. It is an attempt to present selected topics in trigonometry from a historic point of view and to show their relevance to other sciences. It grew out of my love affair with the subject, but also out of my frustration at the way it is being taught in our colleges.
posted by Wolfdog on Mar 24, 2010 - 18 comments

MathTV is a real problem solver for many. It is also found on YouTube, and is free. Here is some background.
posted by Brian B. on Mar 21, 2009 - 8 comments

Norman Wildberger's New Trigonometry Dr Norman Wildberger has rewritten the arcane rules of trigonometry and eliminated sines, cosines and tangents from the trigonometric toolkit. The First chapter of his new book, Divine Proportions, is online (.pdf).
posted by Kwantsar on Sep 25, 2005 - 21 comments

64=65? there must be some kind of trick to this, right?
posted by pyramid termite on Aug 18, 2004 - 30 comments