| .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de) |
| .\" Distributed under GPL |
| .\" |
| .TH CASIN 3 2008-08-11 "" "Linux Programmer's Manual" |
| .SH NAME |
| casin, casinf, casinl \- complex arc sine |
| .SH SYNOPSIS |
| .B #include <complex.h> |
| .sp |
| .BI "double complex casin(double complex " z ); |
| .br |
| .BI "float complex casinf(float complex " z ); |
| .br |
| .BI "long double complex casinl(long double complex " z ); |
| .sp |
| Link with \fI\-lm\fP. |
| .SH DESCRIPTION |
| The |
| .BR casin () |
| function calculates the complex arc sine of |
| .IR z . |
| If \fIy\ =\ casin(z)\fP, then \fIz\ =\ csin(y)\fP. |
| The real part of |
| .I y |
| is chosen in the interval [\-pi/2,pi/2]. |
| .LP |
| One has: |
| .nf |
| |
| casin(z) = \-i clog(iz + csqrt(1 \- z * z)) |
| .fi |
| .SH VERSIONS |
| These functions first appeared in glibc in version 2.1. |
| .SH "CONFORMING TO" |
| C99. |
| .SH "SEE ALSO" |
| .BR clog (3), |
| .BR csin (3), |
| .BR complex (7) |
