# The unit circle definition of the trigonometric functions

3 videos
1 skill
Learn about the ingenious way in which we define the trigonometric functions for any real number.

### The unit circle definition of sine, cosine, and tangent

VIDEO 9:04 minutes
Sal shows how we can extend SOH CAH TOA so that we can define trig functions for all real numbers.

### How to find trigonometric values using the unit circle definition (example)

VIDEO 4:12 minutes
Sal finds sin(275°), sin(-55°), sin(2/3*π), sin(15°), cos(2π), and cos(1/12*π) using the unit circle definition.

### Find trig values using the unit circle definition

PRACTICE PROBLEMS
Given the unit circle and an angle measure, find one of its trigonometric values using the unit circle definition of the trigonometric functions.

### Matching the SOH CAH TOA and the unit circle definitions of the trigonometric functions

VIDEO 6:57 minutes
Sal shows how, for acute angles, the two different definitions of the trigonometric values result in the same values.