PHP acosh function

acosh

(PHP 4 >= 4.1.0, PHP 5)

acosh — Inverse hyperbolic cosineDescriptionfloat 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().