Synopsis:
    #include <math.h>
    double tanh( double x );

Description:
    The tanh function computes the hyperbolic tangent of x.

    When the x argument is large, partial or total loss of significance may
    occur.  The  matherr function will be invoked in this case.

Returns:
    The tanh function returns the hyperbolic tangent value.  When an error
    has occurred,  errno contains a value indicating the type of error that
    has been detected.

Example:
    #include <stdio.h>
    #include <math.h>

    void main()
      {
        printf( "%f\n", tanh(.5) );
      }

    produces the following:

    0.462117

Classification:
    ANSI

Systems:
    Math

See Also:
    cosh, sinh, matherr