Cosine, Sine and the Unit Circle

Chose either the sine or cosine to trace. Select the animate button. Select either show sine or show cosine to see how well what you traced matches the graph.
Press "Ctrl F" to remove previous traces.

Questions:
1. Look at the values of the unit circle, angle measure, and the sine. What do you notice? How does this mean the sine relates to the unit circle? Do the same with the cosine.

2. The angle is measured in radians, not in degrees. Why do you think this is so?

Dixie Christensen, 26 October 2013, Created with GeoGebra