.\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
.\" Distributed under GPL
.\"
.TH CATANH 3 2002-07-28 "" "complex math routines"
.SH NAME
catanh, catanhf, catanhl \- complex arc tangents hyperbolic
.SH SYNOPSIS
.B #include <complex.h>
.sp
.BI "double complex catanh(double complex " z ); 
.br
.BI "float complex catanhf(float complex " z );
.br
.BI "long double complex catanhl(long double complex " z );
.sp
Link with \-lm.
.SH DESCRIPTION
The 
.BR catanh () 
function calculates the complex atanh().
If y = catanh(z), then z = ctanh(y).
The imaginary part of y is chosen in the interval [\-pi/2,pi/2].
.LP
One has catanh(z) = 0.5*clog((1+z)/(1\-z)).
.SH "CONFORMING TO"
C99
.SH "SEE ALSO"
.BR atanh (3),
.BR cabs (3),
.BR cimag (3),
.BR complex (7)