What is the unit circle definition of the trigonometric functions? The unit circle definition allows us to extend the domain of sine and cosine to all real numbers.

For each point on the unit circle, select the angle that corresponds to it. Click each dot on the image to select an answer.

Oops. Something went wrong. Please try again. Uh oh, it looks like we ran into an error. You need to refresh. If this problem persists, tell us.

Sal finds trigonometric identities for sine and cosine by considering angle rotations on the unit circle.

Given the value of a trigonometric function for an angle x, use the unit circle to find the value for related angle measures.

Sal finds several trigonometric identities for sine and cosine by considering horizontal and vertical symmetries of the unit circle.

Learn the relationship between the radius, diameter, and circumference of a circle.

For each point on the unit circle, select the angle that corresponds to it. Click each dot on the image to select an answer.

Khan Academy Sign up

The area of a circle is pi times the radius squared (A = π r²). Learn how to use this formula to find the area of a circle when given the diameter. Created by Sal Khan and Monterey Institute for …