vcaa questions

[allstar]

i have a question from the 2003 vcaa exam paper
question 3a)

I know OC vector is -2i +5j - 2k
and that AB vector is also -2i +5j - 2k, what does this show? and is that all i have to do to ans this question?

[keltingmeith]

That shows that OC and AB are the same vector - in this case, just that they're parallel. There are two more things you need to show:

OA=CB, and that |OA|=|OC|=|CB|=|AB|

Note that geometric proofs like this are not specified for the exam in the current study design.