atan(3M)
NAME
atan − arc tangent function
SYNOPSIS
cc [ flag ... ] file ... −lm [ library ... ]
#include <math.h>
double atan(double x);
DESCRIPTION
The atan() function computes the principal value of the arc tangent of x.
RETURN VALUES
Upon successful completion, atan() returns the arc tangent of x in the range [−π/2,π/2] radians.
If x is NaN, NaN is returned.
If x is ±Inf, ±π/2 is returned.
ERRORS
No errors will occur.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| MT-Level | MT-Safe |
SEE ALSO
atan2(3M), isnan(3M), tan(3M), attributes(5)
SunOS 5.6 — Last change: 29 Dec 1996