hyperbolic cosine

In mathematics, hyperbolic functions are analogs of the ordinary trigonometric, or circular functions. The basic hyperbolic functions are the hyperbolic sine "sinh" ( or ), and the hyperbolic cosine "cosh" , from which are derived the hyperbolic tangent "tanh" ( or ), hyperbolic cosecant "csch" or "cosech" ( or ), hyperbolic secant "sech" ( or ), and hyperbolic cotangent "coth" ( or ), corresponding to the derived trigonometric functions. The inverse hyperbolic functions are the area hyperbolic sine "arsinh" (also called "asinh" or sometimes "arcsinh") and so on.