Description
ACOS function calculates the arc cosine of @x; that is the value whose cosine is @x. If @x falls outside the range -1 to 1, ACOS fails and returns the #NUM! error. The value it returns is in radians.
This function is Excel compatible.
Examples
ACOS(0.1) equals 1.470629.
ACOS(-0.1) equals 1.670964.