Posted by **Anonymous** on Saturday, March 29, 2008 at 2:23pm.

I have a test on monday and I need help with these two questions, please.

1)Prove that the magnitude of the vector OP = (a,b,c) is given by |OP| = sqrt a^2+b^2+c^2

I understand how to find the magnitude, but I don't know how to prove it.

2)Give a geometrical interpretation of the vector u = (4,2,-5,2)

Do I just draw a paralellogram?