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The purpose of this applet is to illustrate the relation between a point on the unit circle, its coordinates and the angle between the x-axis and the line through the origin and the point. Use it as follows: Drag the point around the unit circle, clockwise or counterclockwise, as many times as you want. As you do so, the following should happen:

1. The coordinates of the point will be updated.
2. The value of the angle between the x-axis and the line through the origin and the point will show only if you have selected to display it. In this case, it will be displayed in the chosen units (degrees or radians).
3. The point will be in green if it corresponds to a positive angle, otherwise it will be red.