Relationship Between Unit Circle and Sine/ Cosine Curve

This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com

Directions: Click the Animate Point A button to show the sine and cosine graph and how they relate to the unit circle.
What relation does alpha and point A on the unit circle have to the point S on the sine graph?
What relation does alpha and point A on the unit circle have to the point C on the cosine graph?

Megan Urbanik, 24 October 2013, Created with GeoGebra