ATAN

Section: Linux Programmer's Manual (3)
Updated: 2002-07-27
Index Return to Main Contents
 

NAME

atan, atanf, atanl - arc tangent function  

SYNOPSIS

#include <math.h>

double atan(double x);

float atanf(float x);
long double atanl( long double x);
Link with -lm.  

DESCRIPTION

The atan() function calculates the arc tangent of x; that is the value whose tangent is x.  

RETURN VALUE

The atan() function returns the arc tangent in radians and the value is mathematically defined to be between -PI/2 and PI/2 (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), atan2(3), carg(3), catan(3), cos(3), sin(3), tan(3)


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
CONFORMING TO
SEE ALSO

linux.jgfs.net manual pages