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) ; |
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)
Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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manual page may be incorrect or out-of-date. The author(s) assume no
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the use of the information contained herein. The author(s) may not
have taken the same level of care in the production of this manual,
which is licensed free of charge, as they might when working
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Formatted or processed versions of this manual, if unaccompanied by
the source, must acknowledge the copyright and authors of this work.
References consulted:
Linux libc source code
Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
386BSD man pages
Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
Modified 2002-07-27 by Walter Harms
(walter.harms@informatik.uni-oldenburg.de)
|