Trigonometric Functions: The Unit Circle
In the 1600s, scientists began using trigonometry to solve problems in physics and engineering.
Such applications necessitated extending the domains of the trigonometric functions to include all real numbers, not just a set of angles. This extension was accomplished by using a correspondence between an angle and the length of an arc on a unit circle.
The two historical perspectives of trigonometry incorporate different methods for introducing the trigonometric functions. Our first introduction to these functions is based on the unit circle.
Find out more about evaluating trigonometric functions using the unit circle below.
Trigonometric Functions The Unit Circle
Practice: Determine the values of the trigonometric functions using the unit circle in the exercises below.