cacosh(3)

1CACOSH(3)                  Linux Programmer's Manual                 CACOSH(3)
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NAME

6       cacosh, cacoshf, cacoshl - complex arc hyperbolic cosine
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SYNOPSIS

9       #include <complex.h>
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11       double complex cacosh(double complex z);
12       float complex cacoshf(float complex z);
13       long double complex cacoshl(long double complex z);
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15       Link with -lm.
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DESCRIPTION

18       These  functions  calculate the complex arc hyperbolic cosine of z.  If
19       y = cacosh(z), then z = ccosh(y).  The imaginary part of y is chosen in
20       the interval [-pi,pi].  The real part of y is chosen nonnegative.
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22       One has:
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24           cacosh(z) = 2 * clog(csqrt((z + 1) / 2) + csqrt((z - 1) / 2))
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VERSIONS

27       These functions first appeared in glibc in version 2.1.
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ATTRIBUTES

30       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
31       tributes(7).
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33       ┌───────────────────────────────┬───────────────┬─────────┐
34       │Interface                      │ Attribute     │ Value   │
35       ├───────────────────────────────┼───────────────┼─────────┤
36       │cacosh(), cacoshf(), cacoshl() │ Thread safety │ MT-Safe │
37       └───────────────────────────────┴───────────────┴─────────┘

CONFORMING TO

39       C99, POSIX.1-2001, POSIX.1-2008.
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EXAMPLES

42       /* Link with "-lm" */
43
44       #include <complex.h>
45       #include <stdlib.h>
46       #include <unistd.h>
47       #include <stdio.h>
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49       int
50       main(int argc, char *argv[])
51       {
52           double complex z, c, f;
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54           if (argc != 3) {
55               fprintf(stderr, "Usage: %s <real> <imag>\n", argv[0]);
56               exit(EXIT_FAILURE);
57           }
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59           z = atof(argv[1]) + atof(argv[2]) * I;
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61           c = cacosh(z);
62           printf("cacosh() = %6.3f %6.3f*i\n", creal(c), cimag(c));
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64           f = 2 * clog(csqrt((z + 1)/2) + csqrt((z - 1)/2));
65           printf("formula  = %6.3f %6.3f*i\n", creal(f2), cimag(f2));
66
67           exit(EXIT_SUCCESS);
68       }
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COLOPHON

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81                                  2020-06-09                         CACOSH(3)