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ACOSH(3) Linux Programmer's Manual ACOSH(3)

acosh, acoshf, acoshl - inverse hyperbolic cosine function

#include <math.h>
double acosh(double x);
float acoshf(float x);
long double acoshl(long double x);


Link with -lm.




Feature Test Macro Requirements for glibc (see
  feature_test_macros(7)):


acosh():


_ISOC99_SOURCE ||
  _POSIX_C_SOURCE >= 200112L


 || _XOPEN_SOURCE >= 500


 || /* Since glibc 2.19: */ _DEFAULT_SOURCE


 || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE



acoshf(), acoshl():

_ISOC99_SOURCE ||
  _POSIX_C_SOURCE >= 200112L


 || /* Since glibc 2.19: */ _DEFAULT_SOURCE


 || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE








These functions calculate the inverse hyperbolic cosine of
    x; that is the value whose hyperbolic cosine is x.








On success, these functions return the inverse hyperbolic cosine
    of x.


If x is a NaN, a NaN is returned.


If x is +1, +0 is returned.


If x is positive infinity, positive infinity is
  returned.


If x is less than 1, a domain error occurs, and the
    functions return a NaN.








See math_error(7) for information on how to determine
    whether an error has occurred when calling these functions.


The following errors can occur:



  

  
errno is set to EDOM. An invalid floating-point exception
      (FE_INVALID) is raised.










For an explanation of the terms used in this section, see
    attributes(7).



  

    Interface
    Attribute
    Value
  

  

    acosh (), acoshf (), acoshl ()
    Thread safety
    MT-Safe
  










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


The variant returning double also conforms to SVr4,
  4.3BSD.








asinh(3), atanh(3), cacosh(3),
    cosh(3), sinh(3), tanh(3)








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    the latest version of this page, can be found at
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    2017-09-15