relibc_openlibm/man/acos.3

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.\"     from: @(#)acos.3	5.1 (Berkeley) 5/2/91
.\" $FreeBSD: src/lib/msun/man/acos.3,v 1.15 2008/07/31 22:41:26 das Exp $
.\"
.Dd July 31, 2008
.Dt ACOS 3
.Os
.Sh NAME
.Nm acos ,
.Nm acosf ,
.Nm acosl
.Nd arc cosine functions
.Sh LIBRARY
.Lb libm
.Sh SYNOPSIS
.In math.h
.Ft double
.Fn acos "double x"
.Ft float
.Fn acosf "float x"
.Ft long double
.Fn acosl "long double x"
.Sh DESCRIPTION
The
.Fn acos ,
.Fn acosf ,
and
.Fn acosl
functions compute the principal value of the arc cosine of
.Fa x .
.Sh RETURN VALUES
These functions return the arc cosine in the range
.Bq 0 , \*(Pi
radians.
If:
.Bd -unfilled -offset indent
.Pf \&| Ns Ar x Ns \&| > 1 ,
.Ed
.Pp
.Fn acos x
raises an invalid exception and returns an \*(Na.
.Sh SEE ALSO
.Xr asin 3 ,
.Xr atan 3 ,
.Xr atan2 3 ,
.Xr cos 3 ,
.Xr cosh 3 ,
.Xr fenv 3 ,
.Xr math 3 ,
.Xr sin 3 ,
.Xr sinh 3 ,
.Xr tan 3 ,
.Xr tanh 3
.Sh STANDARDS
The
.Fn acos ,
.Fn acosf ,
and
.Fn acosl
functions conform to
.St -isoC-99 .