# Homework Help: Vector help!

1. Feb 9, 2013

### organgeatom

1. The problem statement, all variables and given/known data
I cannot find other sources to help me with this problem set, I have A B and C vectors defined by: A (2,1,1) B(1,-1,0), C(-1,1,-1)
From these I have a list of questions and some I am stuck on are:each of these are vectors with an arrow above it
1. |A| + |B| this I did as √ax^2 +ay^2 +az^2 + √the same for B
2. |A + B| but how do i do this, what is the difference between these?

3. A + B

4. 3C

5. A dot (B X C)

8. What is the angle between A and B, A and C, and B and C? in radians use pi

id appreciate any help!!

2. Feb 9, 2013

### rock.freak667

This would be correct.

This is asking for you the magnitude of (vector A + vector B), question 1 was asking you for the magnitude of vector A + the magnitude of vector B. Start by first calculating what A+B is, how do you add two vectors together?

The same as question 2.

Do you know how to multiply a vector by a scalar?

Do you know the terms 'dot product' and 'cross-product'?

This question depends on if you can do question 5.

3. Feb 10, 2013

### Ferramentarius

Wikipedia explains the basic properties of vectors such as addition, scalar multiplication, length as well as dot and cross products.