| .\" Copyright 2002 Walter Harms(walter.harms@informatik.uni-oldenburg.de) |
| .\" Distributed under GPL |
| .\" |
| .TH CACOSH 3 2007-12-26 "" "Linux Programmer's Manual" |
| .SH NAME |
| cacosh, cacoshf, cacoshl \- complex arc hyperbolic cosine |
| .SH SYNOPSIS |
| .B #include <complex.h> |
| .sp |
| .BI "double complex cacosh(double complex " z ); |
| .br |
| .BI "float complex cacoshf(float complex " z ); |
| .br |
| .BI "long double complex cacoshl(long double complex " z ); |
| .sp |
| Link with \fI\-lm\fP. |
| .SH DESCRIPTION |
| The |
| .BR cacosh () |
| function calculates the complex arc hyperpolic cosine of |
| .IR z . |
| If \fIy\ =\ cacosh(z)\fP, then \fIz\ =\ ccosh(y)\fP. |
| The imaginary part of |
| .I y |
| is chosen in the interval [\-pi,pi]. |
| The real part of |
| .I y |
| is chosen non-negative. |
| .LP |
| One has: |
| .nf |
| |
| cacosh(z) = (0.5) * clog((1 + z) / (1 \- z)) |
| .fi |
| .SH "CONFORMING TO" |
| C99. |
| .SH "SEE ALSO" |
| .BR acosh (3), |
| .BR cabs (3), |
| .BR cimag (3), |
| .BR complex (7) |
