1*61283Sbostic.\" Copyright (c) 1991, 1993 2*61283Sbostic.\" The Regents of the University of California. All rights reserved. 348917Scael.\" 448917Scael.\" %sccs.include.redist.man% 548917Scael.\" 6*61283Sbostic.\" @(#)acos.3 8.1 (Berkeley) 06/04/93 748917Scael.\" 848917Scael.Dd 948917Scael.Dt ACOS 3 1048917Scael.Os 1148917Scael.Sh NAME 1248917Scael.Nm acos 1348917Scael.Nd arc cosine function 1448917Scael.Sh SYNOPSIS 1548917Scael.Fd #include <math.h> 1648917Scael.Ft double 1748917Scael.Fn acos "double x" 1848917Scael.Sh DESCRIPTION 1948917ScaelThe 2048917Scael.Fn acos 2148917Scaelfunction computes the principal value of the arc cosine of 2248917Scael.Fa x . 2348917ScaelA domain error occurs for arguments not in the range [-1, +1]. 2448917ScaelFor a discussion of error due to roundoff, see 2548917Scael.Xr math 3 . 2648917Scael.Sh RETURN VALUES 2748917ScaelThe 2848917Scael.Fn acos 2948917Scaelfunction returns the arc cosine in the range 3048917Scael.Bq 0 , \*(Pi 3148917Scaelradians. 3248917ScaelOn the 3348917Scael.Tn VAX 3448917Scaeland 3548917Scael.Tn Tahoe , 3648917Scaelif: 3748917Scael.Bd -unfilled -offset indent 3848917Scael.Pf \&| Ns Ar x Ns \&| > 1 , 3948917Scael.Ed 4048917Scael.Pp 4148917Scael.Fn acos x 4248917Scaelsets the global variable 4348917Scael.Va errno 4448917Scaelto 4548917Scael.Dv EDOM 4648917Scaeland a reserved operand fault is generated. 4748917Scael.Sh SEE ALSO 4848917Scael.Xr sin 3 , 4948917Scael.Xr cos 3 , 5048917Scael.Xr tan 3 , 5148917Scael.Xr asin 3 , 5248917Scael.Xr atan 3 , 5348917Scael.Xr atan2 3 , 5448917Scael.Xr sinh 3 , 5548917Scael.Xr cosh 3 , 5648917Scael.Xr tanh 3 , 5748917Scael.Xr math 3 , 5848917Scael.Sh STANDARDS 5948917ScaelThe 6048917Scael.Fn acos 6148917Scaelfunction conforms to 6248917Scael.St -ansiC . 63