Wolfram Research
Wolfram Math World: Cosine
Graphs of the cosine function, both 2-dimensional and 3-dimensional. Higher level mathematics applications given, including defining the hyperbolic cosine function, the cosine function as an infinite sum and infinite product, and more.
Interactive Mathematics
Interactive Mathematics: Graphs of Sine and Cosine Functions
An interactive graph provides a demonstration to show how the measure of an angle is related to the sine and cosine waves. Topics covered include amplitude and period. Examples allow students to practice the concepts.