Homework Help: Determine if three vectors form a right hand triple?

1. Sep 10, 2008

fredrick08

1. The problem statement, all variables and given/known data
ok can someone tell me how to determine if three vectors form a right hand triple? and why does (a-b)x(a+b)=2(axb)....

plz someone help, im really confused on how to do these.... arent just three vectors a right hand triple if the dot product between them all is 0?? im not sure though plz someone help.. and the second one.. the must be a formula or a property i cant find... thanks

2. Sep 10, 2008

HallsofIvy

Re: vectors

Well, first of all what is the definition of "right hand triple"? That would seem a good place to start!

For the second, I assume that you are talking about the cross product of vectors. (a- b)x(a+ b)= what if you just go ahead and multiply it out (the distributive and associative laws of multiplication are true for the cross product). Now remember that cross product if anti-commutative. What is axa? What is bxb?