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

Description:
    The tan function computes the tangent of x (measured in radians).  A
    large magnitude argument may yield a result with little or no
    significance.

Returns:
    The tan function returns the 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", tan(.5) );
      }

    produces the following:

    0.546302

Classification:
    ANSI

Systems:
    Math

See Also:
    atan, atan2, cos, sin, tanh