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ACOS(3)
ACOS(3) FreeBSD Library Functions Manual ACOS(3)

NAME

acos, acosf, acoslarc cosine functions

LIBRARY

Math Library (libm, -lm)

SYNOPSIS

#include < math.h>

double
acos( double x);

float
acosf( float x);

long double
acosl( long double x);

DESCRIPTION

The acos(), acosf(), and acosl() functions compute the principal value of the arc cosine of x.

RETURN VALUES

These functions return the arc cosine in the range [0, pi] radians. If:

|x| > 1,

acos( x) raises an invalid exception and returns an NaN.

STANDARDS

The acos(), acosf(), and acosl() functions conform to ISO/IEC 9899:1999 (“ISO C99”).
July 31, 2008 FreeBSD