[RESOLVED] [2005] cos-1 (arccosine) of a number

[andyismilesaway]

Hi all.

Im trying to get the arccosine of a number eg.

to pseudocode:
angle=arccosine(0.23)

I know its not rocket science, its just im not finding the help overly helpful!!

thanks guys

[bluehairman]

... What is arccosine? I did some Sine, Cosine, and Tangent in school, but never heard of Arccosine. Unless its Tangent -1

[andyismilesaway]

ArcCosine is the button you press to work out the interior angle or a traingle when you know the length of two of the sides.

Its Shift Cos (for ArcCosine) on Casio calcs if that helps!

cheers

[stimbo]

Okay, I've no idea if this is correct but have you checked out the Math functions in .NET.

For example:

Dim myCo As Double = Math.Acos(0.29)
        MessageBox.Show(myCo.ToString)

I haven't checked out what Acos is exactly (something to do with cosine obviously) but there is also Math.Cos so perhaps the A stands for what you are looking for?

Check out Math. and follow the intellisense

[andyismilesaway]

sorted, the confusion came from VB giving the result in radians not degrees as I thought it might
All sorted!

and its ACos that gives the arccosine

[stimbo]

I think that's the first Math question I may have ever got right in my ENTIRE life.

[jmcilhinney]

From the help topic for the Math.Acos method:

Return Value
An angle, θ, measured in radians, such that 0 ≤θ≤π -or- NaN if d < -1 or d > 1.
Remarks
Multiply the return value by 180/π to convert from radians to degrees.

No, not very helpful.