Math Is Fun Forum

Hi..

This is my first post ever in this forum, so hello to everyone

I'm trying to create a game where I use vectors to define the directions.

I use the formula provided in the bottom of this illustration that I've created:
http://i40.tinypic.com/sor9me.jpg

I use the formula to find the angle between the two vectors, but the problem is that it always finds the smallest angle between the vectors.

So the angle between v1 and v2 is 45degress
and the angle between v1 and v3 is also 45 degress.

Is there any way to make the angle between v1 and v2 to -45degress or just make it to 360-45degress.

I have tried something with the dotproduct, but I couldn't figure it out.

I really hope that you have any suggestions

Thansk for you time and help!

Regards Fandus