# Homework Help: Adding and subtracting vectors

1. Oct 20, 2012

### Ammar w

1. The problem statement, all variables and given/known data
The diagram below shows 3 vectors which sum to zero, all of equal length. What is
$\vec{A}$ - $\vec{B}$?

http://s3.amazonaws.com/diigo/thumb...RL]http://www.diigo.com/item/image/2sb3i/jw3s

2. Relevant equations

I don't know but :

$\vec{A}$ - $\vec{B}$ = $\vec{A}$ + (-$\vec{B}$)

3. The attempt at a solution

I have no idea.

Last edited by a moderator: May 6, 2017
2. Oct 20, 2012

### Andrew Mason

What is $\vec C + \vec A$? What would you have to add to that result to get $\vec A - \vec B$ ?

AM

Last edited by a moderator: May 6, 2017
3. Oct 20, 2012

### tiny-tim

Welcome to PF!

Hi Ammar w! Welcome to PF!

Draw -B …

what does it look like?

4. Oct 20, 2012

### Ammar w

Thank you Andrew Mason & tiny-tim
C+A=-B // add A to the sides of the equatoin
C+2A=A-B
A-B = C+2A.
I didn't draw anything.
Thanks for let me thinking.

5. Oct 20, 2012

### Ammar w

Thank you Andrew Mason & tiny-tim
C+A=-B // add A to the sides of the equatoin
C+2A=A-B
A-B = C+2A.
I didn't draw anything.
Thanks for let me thinking.