1.\" $OpenBSD: casin.3,v 1.2 2013/06/05 03:40:26 tedu Exp $ 2.\" 3.\" Copyright (c) 2011 Martynas Venckus <martynas@openbsd.org> 4.\" 5.\" Permission to use, copy, modify, and distribute this software for any 6.\" purpose with or without fee is hereby granted, provided that the above 7.\" copyright notice and this permission notice appear in all copies. 8.\" 9.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16.\" 17.Dd $Mdocdate: June 5 2013 $ 18.Dt CASIN 3 19.Os 20.Sh NAME 21.Nm casin , 22.Nm casinf , 23.Nm casinl 24.Nd complex circular arc sine 25.Sh SYNOPSIS 26.In complex.h 27.Ft double complex 28.Fn casin "double complex z" 29.Ft float complex 30.Fn casinf "float complex z" 31.Ft long double complex 32.Fn casinl "long double complex z" 33.Sh DESCRIPTION 34The 35.Fn casin , 36.Fn casinf 37and 38.Fn casinl 39functions compute the complex circular arc sine of 40.Fa z . 41.Pp 42For all complex floating-point numbers 43.Fa z , 44.Bd -literal -offset indent 45casin(z) = -i clog(iz + csqrt(1 - z^2)). 46.Ed 47.Sh RETURN VALUES 48The 49.Fn casin , 50.Fn casinf 51and 52.Fn casinl 53functions return the complex circular arc sine of 54.Fa z 55with unbounded imaginary part, and real part in the interval 56.Bq -Pi/2, Pi/2 . 57.Sh SEE ALSO 58.Xr cacos 3 , 59.Xr catan 3 60.Sh STANDARDS 61The 62.Fn casin , 63.Fn casinf 64and 65.Fn casinl 66functions conform to 67.St -isoC-99 . 68