How to add arccos to a formula in property set definitions?

[Anonymous]

Hi,

I can't see the acos function when adding a formula parameter in property set definitions. Isn't it available?

Using AutoCAD MEP 2015

Thanks

[Keith.Brown · Accepted solution]

No it is not.  

VBScript does not have an arccos or arcsin function.  It does have an arctan function though so you need to express it in terms of arctan.

    ArcSin = Atn(X / Sqr(-X * X + 1))

    ArcCos = Atn(-X / Sqr(-X * X + 1)) + 2 * Atn(1)

I believe that my formulas are correct but you might want to double check.

[Anonymous]

Thanks a lot! That does the trick