ACOSH(3)               FreeBSD Library Functions Manual               ACOSH(3)

NAME
     acosh, acoshf, acoshl - inverse hyperbolic cosine functions

LIBRARY
     Math Library (libm, -lm)

SYNOPSIS
     #include <math.h>

     double
     acosh(double x);

     float
     acoshf(float x);

     long double
     acoshl(long double x);

DESCRIPTION
     The acosh(), acoshf(), and acoshl() functions compute the inverse
     hyperbolic cosine of the real argument x.  For a discussion of error due
     to roundoff, see math(3).

RETURN VALUES
     These functions return the inverse hyperbolic cosine of x.  If the
     argument is less than 1, acosh() raises an invalid exception and returns
     an NaN.

SEE ALSO
     asinh(3), atanh(3), exp(3), fenv(3), math(3)

HISTORY
     The acosh(), acoshf(), and acoshl() functions appeared in 4.3BSD,
     FreeBSD 2.0, and FreeBSD 10.0, respectively.

FreeBSD 13.1-RELEASE-p6          June 9, 2013          FreeBSD 13.1-RELEASE-p6