VBA - Can't get COS to give me the right value.

[swayp11]

For some reason, I can't get COS to evaluate correctly for certain values.

Dim Pi As Double
Pi = 3.14159265358979




Debug.Print (Cos(0))
Debug.Print (Cos(Pi / 2))
Debug.Print (Cos(Pi))
Debug.Print (Cos(3 * Pi / 2))
Debug.Print (Cos(2 * Pi))

The results I get are:

 1 
 1.61554255216634E-15 
-1 
-4.62458305157398E-15 
 1

But it should be 1, 0, -1, 0 ,1. Why is not calculating correctly when it should evaluate to 0?

Thanks!

 

[shg]

The values that should be zero are very close to it, and the error is probably a result of the Taylor series (polynomial) approximation used to calculate it. You can use round(cos(angle), 15).

 

[swayp11]

Thank you this worked!

 

[shg]

You're welcome.