Originally Posted by

**tecne** Hi all,

I have 3 pairs of 3-dimensional unit vectors. I take the dot product of those pairs of vectors and so I obtain the angle between them. In other words I can express the three dot products by their respective angle $\displaystyle \cos\theta_1$, $\displaystyle \cos\theta_2$ and $\displaystyle \cos\theta_3$. I was wondering if there is any interesting geometric interpretation by the addition of those three angles $\displaystyle \cos\theta_1$ + $\displaystyle \cos\theta_2$ + $\displaystyle \cos\theta_3$?

I am trying to find a way of simplifying/re-writing the above addition of angles and hence express it as a single term.

I would appreciate anyones help

Regards

Alex