Preparation. You should be familiar with the radian measure of an angle. For a review, go to Kinematics/Angle/Get Information and Kinematics/Angle/Simulate It.

The applet on Page 2 allows movement of a point on a unit circle and displays the projections equal to the sine and the cosine of the angle defined by the point on the unit circle. The applet draws the graphs of the sine, cosine, tangent, and cotangent functions as the point on the unit circle is moved. The range of the angle is from minus to plus infinity.