ACOSH (Primitive Spread Function) returns the inverse hyperbolic cosine of the specified value.
SYNTAX:
ACOSH(value)
REMARKS:
For the value argument, you can specify any real number greater than or equal to 1.
Note that acosh(cosh(value)) = value.
EXAMPLES:
ACOSH(1)=0
ACOSH(10)=2.9932228461