Expressions Returning NaN

Hello, I have an expression that takes 3 values of type double and should return an angle. Instead, the expression returns NaN.
How can I assure that the expression doesn’t return NaN? (3.7 KB)

An ACos(x) can’t return a value if x is less than -1 or more than 1 !

Maybe you need to use rad


Tysm! I had to put 2ac in parentheses, but your reply helped nonetheless.