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