tanh, tanhf---hyperbolic tangent

#include <math.h>
double tanh(double x);
float tanhf(float x);

tanh computes the hyperbolic tangent of the argument x. Angles are specified in radians.

tanh(x) is defined as

 sinh(x)/cosh(x)

Returns
The hyperbolic tangent of x is returned.

Portability
tanh is ANSI C. tanhf is an extension.