using arccos(x) function - Visual Basic

[Tag_yer_dead]

hey everybody,
I have a question involving visual basic -
im creating a program that allows you to draw a triangle, and will then compute the side lengths and
angle measurements.  However, i need to use inverse cosine to figure the angles out.

I know the formula for inverse cosine is
Arccos(X) = Atn(-X / Sqr(-X * X + 1)) + 2 * Atn(1)

I get the error "Invalid Call Procedure, or Argument"
and arccos(x)=empty

If any one knows how to use the function, please give me some example code.
Thanks alot

[Sidewinder]

In order to make the ArcCos function call, you need to define the function:

Code: [Select]

myVar = ArcCos(arg)

Public Function ArcCos(X As Double) As Double
   ArcCos = Atn(-X / Sqr(-X * X + 1)) + 2 * Atn(1)
End Function

Hope this helps.