Vector in three dimensions

1. May 16, 2007

fffff

1. The problem statement, all variables and given/known data

Point A (2i +j 2k)
Point B (3i +2j +5k)
Point C (4i +5j -2k)

the point d is such that abcd in that order is a parallelogram.

Find position Vector D

2. Relevant equations

3. The attempt at a solution

ok so i start of like this but im getting the wrong answer.

(BA)^1/2=(CD)^1/2

but its wrong.

2. May 16, 2007

NateTG

It might be useful to make a drawing.

3. May 16, 2007

fffff

Yes, but are those equations correct
I've realized my error.
culd you tell me the point of the unit vector.

Last edited: May 16, 2007
4. May 16, 2007

NateTG

You don't need to do anything involving norms or unit vectors here, so the square root stuff is way off base. It's really just a matter of vector addition, and subtraction.

$$\vec{BA}=\vec{OD} - \vec {OC}$$
makes sense to me, the other equations don't really.