#
The Cosine Curve

Blue Length = Blue Length; Green Length = Green Length

The x-coordinate of the point on the unit circle determined by a
central angle (in standard position) of x radians is Cos(x). In a
unit
circle, the radian measure of an angle is the length of the arc
subtended by that angle. To the left of the y-axis, you see a unit
circle being swept out, with the radian measure of the angle (arc
length) shown in blue, and the cosine of that angle (the
x-coordinate)
shown in green. To the right of the y-axis, you see the points of
the
graph of y = Cos(x) being graphed in black. The angle x is shown
in
blue and the value of Cos(x) is shown in green.

### Other Animated Sites

The Sine Curve

The Area of a Circle

The Area of a Circle II

The Pythagorean Theorem

WKU
Mathematics Department .|. WKU
Online

*Last updated, Jan. 29, 2008*

Tom.Richmond@WKU.edu