man3/cacosh.3

   1 .\" Copyright 2002 Walter Harms(walter.harms@informatik.uni-oldenburg.de)
   2 .\" and Copyright (C) 2011 Michael Kerrisk <mtk.manpages@gmail.com>
   3 .\"
   4 .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
   5 .\" Distributed under GPL
   6 .\" %%%LICENSE_END
   7 .\"
   8 .TH CACOSH 3 2015-04-19 "" "Linux Programmer's Manual"
   9 .SH NAME
  10 cacosh, cacoshf, cacoshl \- complex arc hyperbolic cosine
  11 .SH SYNOPSIS
  12 .B #include <complex.h>
  13 .PP
  14 .BI "double complex cacosh(double complex " z );
  15 .br
  16 .BI "float complex cacoshf(float complex " z );
  17 .br
  18 .BI "long double complex cacoshl(long double complex " z );
  19 .PP
  20 Link with \fI\-lm\fP.
  21 .SH DESCRIPTION
  22 These functions calculate the complex arc hyperbolic cosine of
  23 .IR z .
  24 If \fIy\ =\ cacosh(z)\fP, then \fIz\ =\ ccosh(y)\fP.
  25 The imaginary part of
  26 .I y
  27 is chosen in the interval [\-pi,pi].
  28 The real part of
  29 .I y
  30 is chosen nonnegative.
  31 .PP
  32 One has:
  33 .PP
  34 .nf
  35     cacosh(z) = 2 * clog(csqrt((z + 1) / 2) + csqrt((z \- 1) / 2))
  36 .fi
  37 .SH VERSIONS
  38 These functions first appeared in glibc in version 2.1.
  39 .SH ATTRIBUTES
  40 For an explanation of the terms used in this section, see
  41 .BR attributes (7).
  42 .TS
  43 allbox;
  44 lbw30 lb lb
  45 l l l.
  46 Interface       Attribute       Value
  47 T{
  48 .BR cacosh (),
  49 .BR cacoshf (),
  50 .BR cacoshl ()
  51 T}      Thread safety   MT-Safe
  52 .TE
  53 .SH CONFORMING TO
  54 C99, POSIX.1-2001, POSIX.1-2008.
  55 .SH EXAMPLE
  56 .EX
  57 /* Link with "\-lm" */
  58
  59 #include <complex.h>
  60 #include <stdlib.h>
  61 #include <unistd.h>
  62 #include <stdio.h>
  63
  64 int
  65 main(int argc, char *argv[])
  66 {
  67     double complex z, c, f;
  68
  69     if (argc != 3) {
  70         fprintf(stderr, "Usage: %s <real> <imag>\\n", argv[0]);
  71         exit(EXIT_FAILURE);
  72     }
  73
  74     z = atof(argv[1]) + atof(argv[2]) * I;
  75
  76     c = cacosh(z);
  77     printf("cacosh() = %6.3f %6.3f*i\\n", creal(c), cimag(c));
  78
  79     f = 2 * clog(csqrt((z + 1)/2) + csqrt((z \- 1)/2));
  80     printf("formula  = %6.3f %6.3f*i\\n", creal(f2), cimag(f2));
  81
  82     exit(EXIT_SUCCESS);
  83 }
  84 .EE
  85 .SH SEE ALSO
  86 .BR acosh (3),
  87 .BR cabs (3),
  88 .BR ccosh (3),
  89 .BR cimag (3),
  90 .BR complex (7)