If you're seeing this message, it means we're having trouble loading external resources for Khan Academy.
If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.
The unit circle definition of the trigonometric functions
Learn about the ingenious way in which we define the trigonometric functions for any real number.
Sal shows how we can extend SOH CAH TOA so that we can define trig functions for all real numbers.
Sal finds sin(275°), sin(-55°), sin(2/3*π), sin(15°), cos(2π), and cos(1/12*π) using the unit circle definition.
Given the unit circle and an angle measure, find one of its trigonometric values using the unit circle definition of the trigonometric functions.
Sal shows how, for acute angles, the two different definitions of the trigonometric values result in the same values.