# Homework Help: Cal III/ Multi-V (vector notation troubles)

1. Sep 12, 2010

### The_Chromer

1. The problem statement, all variables and given/known data
Given vector A = i + j - k and vector B= i - j + k, calculate ||3A-B||.

My work can be found here (I am not literate in Latex markups):
http://img714.imageshack.us/img714/732/sixhomeworkproblems001.jpg [Broken]

I am unfamiliar with the notation of the double bars surrounding this vector combination. I think, and I say that very loosely, that it means to find the normal vector to the plane. If I could get some clarification for that, then I don't think the problem should be too difficult.

2. Relevant equations
Uncertain of problem notation.

3. The attempt at a solution
http://img823.imageshack.us/img823/8554/attempt001.jpg [Broken]

Last edited by a moderator: May 4, 2017
2. Sep 12, 2010

### Whitishcube

You're really close. All you have to do is find the magnitude of that vector. The equation for that is the square root of the sum of all of its components squared.
Sqrt(a^2+b^2+c^2).

3. Sep 12, 2010

### The_Chromer

Wow. So all the question asks for is the magnitude?

$$sqrt(36)$$=6