ATAN(3) MachTen 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’’).

4.4BSD June 4, 1993 1