man3/catanh.3

   1 .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
   2 .\" and Copyright (C) 2011 Michael Kerrisk <mtk.manpages@gamil.com>
   3 .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
   4 .\" Distributed under GPL
   5 .\" %%%LICENSE_END
   6 .\"
   7 .TH CATANH 3 2011-09-15 "" "Linux Programmer's Manual"
   8 .SH NAME
   9 catanh, catanhf, catanhl \- complex arc tangents hyperbolic
  10 .SH SYNOPSIS
  11 .B #include <complex.h>
  12 .sp
  13 .BI "double complex catanh(double complex " z );
  14 .br
  15 .BI "float complex catanhf(float complex " z );
  16 .br
  17 .BI "long double complex catanhl(long double complex " z );
  18 .sp
  19 Link with \fI\-lm\fP.
  20 .SH DESCRIPTION
  21 The
  22 .BR catanh ()
  23 function calculates the complex arc hyperbolic tangent of
  24 .IR z .
  25 If \fIy\ =\ catanh(z)\fP, then \fIz\ =\ ctanh(y)\fP.
  26 The imaginary part of
  27 .I y
  28 is chosen in the interval [\-pi/2,pi/2].
  29 .LP
  30 One has:
  31 .nf
  32
  33     catanh(z) = 0.5 * (clog(1 + z) \- clog(1 \- z))
  34 .fi
  35 .SH VERSIONS
  36 These functions first appeared in glibc in version 2.1.
  37 .SH CONFORMING TO
  38 C99.
  39 .SH EXAMPLE
  40 .nf
  41 /* Link with "\-lm" */
  42
  43 #include <complex.h>
  44 #include <stdlib.h>
  45 #include <unistd.h>
  46 #include <stdio.h>
  47
  48 int
  49 main(int argc, char *argv[])
  50 {
  51     double complex z, c, f;
  52
  53     if (argc != 3) {
  54         fprintf(stderr, "Usage: %s <real> <imag>\\n", argv[0]);
  55         exit(EXIT_FAILURE);
  56     }
  57
  58     z = atof(argv[1]) + atof(argv[2]) * I;
  59
  60     c = catanh(z);
  61     printf("catanh() = %6.3f %6.3f*i\\n", creal(c), cimag(c));
  62
  63     f = 0.5 * (clog(1 + z) \- clog(1 \- z));
  64     printf("formula  = %6.3f %6.3f*i\\n", creal(f2), cimag(f2));
  65
  66     exit(EXIT_SUCCESS);
  67 }
  68 .fi
  69 .SH SEE ALSO
  70 .BR atanh (3),
  71 .BR cabs (3),
  72 .BR cimag (3),
  73 .BR ctanh (3),
  74 .BR complex (7)