Wolfram Research
Wolfram Math World: Hyperbolic Functions
This site from MathWorld explains the hyperbolic function. The information is not too in-depth, but factual and quite a few links are provided for additional information on related subjects.
Wolfram Research
Wolfram Math World: Tangent
Graphs of the tangent function, both 2-dimensional and 3-dimensional. Higher level mathematics applications given including the hyperbolic tangent function, important relevant identities, the Macluarin series for the tangent function,...