ATAN(3)                     BSD Programmer's Manual                    ATAN(3)

NAME
     atan - arc tangent function of one variable

SYNOPSIS
     #include <math.h>

     double
     atan(double x)

DESCRIPTION
     The atan() function computes the principal value of the arc tangent of x.
     For a discussion of error due to roundoff, see math(3).

RETURN VALUES
     The atan() function returns the arc tangent in the range [-pi/2, +pi/2]
     radians.

SEE ALSO
     acos(3),  asin(3),  atan2(3),  cos(3),  cosh(3),  sin(3),  sinh(3),
     tan(3),  tanh(3),  math(3),

STANDARDS
     The atan() function conforms to ANSI C3.159-1989 (``ANSI C'').

BSDI BSD/386                    March 26, 1993                               1