1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)asin.3 8.1 (Berkeley) 06/04/93 7.\" 8.Dd 9.Dt ASIN 3 10.Os 11.Sh NAME 12.Nm asin 13.Nd arc sine function 14.Sh SYNOPSIS 15.Fd #include <math.h> 16.Ft double 17.Fn asin "double x" 18.Sh DESCRIPTION 19The 20.Fn asin 21function computes the principal value of the arc sine of 22.Fa x . 23A domain error occurs for arguments not in the range [-1, +1]. 24For a discussion of error due to roundoff, see 25.Xr math 3 . 26.Sh RETURN VALUES 27The 28.Fn asin 29function returns the arc sine in the range 30.Bk -words 31.Bq -\*(Pi/2, +\*(Pi/2 32.Ek 33radians. 34On the 35.Tn VAX , 36and Tahoe , 37if: 38.Bd -unfilled -offset indent 39.Pf \&| Ns Ar x Ns \&| > 1 40.Ed 41.Pp 42the 43global variable 44.Va errno 45is set to 46.Er EDOM 47and 48a reserved operand fault generated. 49.Sh SEE ALSO 50.Xr acos 3 , 51.Xr atan 3 , 52.Xr atan2 3 , 53.Xr cos 3 , 54.Xr cosh 3 , 55.Xr sin 3 , 56.Xr sinh 3 , 57.Xr tan 3 , 58.Xr tanh 3 , 59.Xr math 3 , 60.Sh STANDARDS 61The 62.Fn asin 63function conforms to 64.St -ansiC . 65