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ACOS (3) | C library functions | Unix Manual Pages | :man

NAME

acos, acosf - arc cosine functions

CONTENTS

Library
Synopsis
Description
Return Values
See Also
Standards

LIBRARY


.Lb libm

SYNOPSIS


.In math.h double acos "double x" float acosf "float x"

DESCRIPTION

The acos and the acosf functions compute the principal value of the arc cosine of x. A domain error occurs for arguments not in the range [-1, +1]. For a discussion of error due to roundoff, see math(3).

RETURN VALUES

The acos and the acosf functions return the arc cosine in the range [0, pi] radians. If:

| x | > 1,

acos x raises an invalid exception and returns an NaN.

SEE ALSO

asin(3), atan(3), atan2(3), cos(3), cosh(3), fenv(3), math(3), sin(3), sinh(3), tan(3), tanh(3)

STANDARDS

 
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