The Unit Circle and Sine Function

This applet allows you to see the relationship between the unit circle and sine and cosine functions. To use this applet wither move the points or click the animation button. If you would like to see the sine or cosine function click the checkbox to make them appear. You may also use the bar below to increase or decrease the speed of the applet's animation.
Some questions to consider: 1. What is the relationship you see between the sine function and the unit circle? 2. Can you see a relationship between sine and cosine? 3. Would this relationship still apply to other trigonometric identities?