Evaluating trig values using the Unit Circle

Drag the red point around the unit circle.
What is the radius of the circle?
Look carefully at the x & y co-ordinate of the red dot as you move it around the circle.
What do you notice about the numbers?
Compare the values of the x & y co-ordinate of the red dot with the values listed on the left hand side of the figure for Sine & Cosine.
What do you notice?
What are the coordinates of the red dot at [math]\frac{\pi}{2}[/math]?
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– Chris Matthews, Claudette Cardey, user577

Information: Evaluating trig values using the Unit Circle