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Manual Reference Pages  - ACOS (3)

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acos, acosf, acosl - arc cosine function

CONTENTS

Synopsis
Description
Errors

#include <math.h> 



double acos(double x); 

float acosf(float x); 

long double acosl(long double x); 

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.

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

EDOM	x is out of range.

SVID 3, POSIX, BSD 4.3, ISO 9899. The float and long double variants are C99 requirements.

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

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