1.3 Special Triangles using Right Triangle Trig Definitions
Special Triangles and the co-function theorem.
In this section we introduce a definition of the six trigonometric functions for acute angles.
These functions are used to solve for missing parts of a triangle. We also introduce two very
special triangles: the 30°-60°-90° triangle and the 45°-45°-90° triangle. The study of
Trigonometry requires much memorization. Both the definition and the special triangles
presented here should be memorized as soon as possible.
Free textbook: https://www.opentrigonometry.com/2015...