Unit Circle

sin() = 0
cos() = 0

A Unit Circle is a circle plotted with a radius of 1.0 centered on the origin marking the angles 0-360°. The plotted angle (marked in red at ) is draggable or animated. The sine and cosine functions of the angle are marked on their respective axes with perpendicular drop lines from the angle. The cartesian quadrants are shown with traditional Roman numerals, and the quadrant of the plotted angle is highlighted.