#include <cmath>
    double tanh( double arg );

The function tanh() returns the hyperbolic tangent of arg.

C++ also provides the following overloaded forms:

    #include <cmath>
    float tanh( float arg ); // same as tanhf() in C99
    long double tanh( long double arg ); // same as tanhl() in C99

Related Topics: acos, asin, atan, atan2, cos, cosh, sin, sinh, tan