acosh
(PHP 4 >= 4.1.0, PHP 5)
acosh -- Inverse hyperbolic cosine
Description
float
acosh ( float arg)
Returns the inverse hyperbolic cosine of
arg, i.e. the value whose
hyperbolic cosine is arg.
Note: This function is not
implemented on Windows platforms.
See also:
acos(),
asinh(), and
atanh().