ACOS

Section: Linux Programmer's Manual (3)
Updated: 2004-10-06
Index Return to Main Contents
 

NAME

acos, acosf, acosl - arc cosine function  

SYNOPSIS

#include <math.h>

double acos(double x);
float acosf(float x);
long double acosl(long double x);

Link with -lm.  

DESCRIPTION

The acos() function calculates the arc cosine of x; that is the value whose cosine is x. If x falls outside the range -1 to 1, acos() fails and errno is set.  

RETURN VALUE

The acos() function returns the arc cosine in radians and the value is mathematically defined to be between 0 and PI (inclusive).  

ERRORS

EDOM
x is out of range.
 

CONFORMING TO

SVr4, POSIX.1-2001, 4.3BSD, C89. The float and long double variants are C99 requirements.  

SEE ALSO

asin(3), atan(3), atan2(3), cacos(3), cos(3), sin(3), tan(3)


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
CONFORMING TO
SEE ALSO

linux.jgfs.net manual pages