ACOS Returns the arccosine, or inverse cosine, of a number. The arccosine is the angle whose cosine is number. The returned angle is given in radians in the range 0 (zero) to pi.
Syntax
ACOS(number)
Parameters
Number – The cosine of the angle you want and must be from -1 to 1.
Return Value
Returns the arccosine, or inverse cosine, of a number.
Reference Data
https://docs.microsoft.com/en-us/dax/dax-function-reference