Posted 04 May 2006 - 07:22 PM
Can somebody explain how this is done?

Cheers
Posted 04 May 2006 - 09:19 PM
you need to work out a.a (which is just a[^2]
then a.b=|a||b|cosx, where x=60 (equilateral triangle)
and finally a.c= |a||c|cosx, where x=90 (perpendicular)