In mathematics, one of a set of functions related to the hyperbola in the same way the trigonometric function s relate to the circle.
They are the hyperbolic sine, cosine, tangent, secant, cotangent, and cosecant (written "sinh," "cosh," etc.). The hyperbolic equivalent of the fundamental trigonometric identity is cosh 2 z -sinh 2 z = 1. The hyperbolic sine and cosine, particularly useful for finding special types of integral s, can be defined in terms of exponential function s: sinh x = (e x -e -x ) ÷ 2 and cosh x = (e x + e -x ) ÷ 2