1. ## vector question

Based on this diagram http://i55.tinypic.com/2w4wtio.jpg , what is the sum of: ->AB + ->ED + ->CA. Since they have to go head to tail and ED=BC would it be AB + BC + CA? This does not look right to me.

I hope I posted this in the correct forum and I apologize if I did not. Thanks.

2. ## Re: Two vector questions

The way you posted this makes very difficult to read.
If we know that $\displaystyle BCDE$ is a parallelogram then $\displaystyle \overrightarrow {AB} + \overrightarrow {ED} + \overrightarrow {CA} = 0$

3. ## Re: Two vector questions

The base is a square.

4. ## Re: Two vector questions

Originally Posted by Jemde
The base is a square.
Good grief: A square is surely a parallelogram.

5. ## Re: Two vector questions

The base isn't really important. It looks to me like AB+ ED gives us AC. Adding CA takes us back to A. AB+ED+ CA is the 0 vector.

6. ## Re: Two vector questions

Originally Posted by Plato
Good grief: A square is surely a parallelogram.
I know I just thought I should mention it in case it was important. I've just started learning about vectors and I was not sure if you needed to know. Sorry if I caused any confusion. Thanks HallsofIvy and Plato I can see why it equals zero now.