atan2(3) - Linux man page
Name
atan2, atan2f, atan2l - arc tangent function of two variables
Synopsis
#include <math.h>
double atan2(double y, double x);
float atan2f(float y, float x);
long double atan2l(long double y, long double x);
Link with -lm.
Description
The
atan2() function calculates the arc tangent of the two variables
x and
y. It is
similar to calculating the arc tangent of
y /
x, except that the signs of both arguments are used to determine the quadrant of the result.
Return Value
The
atan2() function returns the result in radians, which is between -PI and PI (inclusive).
Conforming to
SVr4, POSIX.1-2001, 4.3BSD, C89. The
float and
long double variants are C99 requirements.
See Also
acos(3),
asin(3),
atan(3),
cos(3),
sin(3),
tan(3)
