Just made this: Interactive Unit Circle
Colors? Style? Should it move on its own? Does it teach anything? Can it do it better?
"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman
Maybe it could be a little larger and the green point on the circle has a tangent being drawn through it. How about providing the equation of that tangent.
In mathematics, you don't understand things. You just get used to them.
I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.