ACOS
Returns an angle, in radians, whose cosine is the specified
value.
Syntax
ACOS(Value)
Value
is a number between -1 and 1 or
a formula which returns a value between -1 and 1. If Value
is outside of these bounds, the result is undefined.
Example
This example returns 1.5708 (pi/2 or 90 degrees):
ACOS(0)
This example returns 0:
ACOS(1)