Trigonometry Introduction, Definition and Periodicity

A short introduction to trigonometry (trig) and trigonometric functions definition and periodicity

Introduction: In mathematics, the trigonometric functions are functions of an angle; they are important when studying triangles and modeling periodic phenomena, among many other applications. They are commonly defined as ratios of two sides of a right triangle containing the angle, and can equivalently be defined as the lengths of various line segments from a unit circle.

Definitions:			Periodicity