acosh(3) [php man page]

ACOSH(3)								 1								  ACOSH(3)

acosh - Inverse hyperbolic cosine

SYNOPSIS

       float acosh (float  $arg)

DESCRIPTION

	Returns the inverse hyperbolic cosine of $arg, i.e. the value whose hyperbolic cosine is $arg.

PARAMETERS

	      o $arg
		- The value to process

RETURN VALUES

	The inverse hyperbolic cosine of $arg

CHANGELOG

       +--------+--------------------------------------------------+
       |Version |						   |
       |	|						   |
       |	|		    Description 		   |
       |	|						   |
       +--------+--------------------------------------------------+
       | 5.3.0	|						   |
       |	|						   |
       |	|  This function is now available on all platforms |
       |	|						   |
       +--------+--------------------------------------------------+
SEE ALSO

       cosh(3), acos(3), asinh(3), atanh(3).

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

NAME

       acosh, acoshf, acoshl - inverse hyperbolic cosine function

SYNOPSIS

       #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(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _ISOC99_SOURCE; or cc -std=c99
       acoshf(), acoshl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99

DESCRIPTION

       The acosh() function calculates the inverse hyperbolic cosine of x; that is the value whose hyperbolic cosine is x.

RETURN VALUE

       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.

ERRORS

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

       The following errors can occur:

       Domain error: x is less than 1
	      errno is set to EDOM.  An invalid floating-point exception (FE_INVALID) is raised.

CONFORMING TO

       C99, POSIX.1-2001.  The variant returning double also conforms to SVr4, 4.3BSD, C89.

SEE ALSO

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

COLOPHON

       This  page is part of release 3.25 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

								    2008-08-05								  ACOSH(3)