# Calc III

1. Feb 1, 2009

### mamma_mia66

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

Find a unit vector that is parallel to the vector from )5,1,-3) to (2,1,1)

2. Relevant equations

3. The attempt at a solution

I will appreciate any HINT for this problem b/c I am totaly confused from the why how the question is stated. Please help.

2. Feb 1, 2009

### NoMoreExams

First find a vector that goes between those 2 points

3. Feb 1, 2009

### Preno

Well, you know what the direction of the vector is, you just have to scale it correctly...

4. Feb 1, 2009

### mamma_mia66

Well, you know what the direction of the vector is, you just have to scale it correctly...

I don't think I get this that I have to scale it correctly...

5. Feb 1, 2009

### NoMoreExams

What's the difference between any old vector and unit vector?

6. Feb 1, 2009

### mamma_mia66

okay, I am following the textbook and nothings helps.

The points (5,1,-3) and (2,1,1) are the points of the vector V=<-3,0,4>

Then ||v||= 5
u= v/||v||= 1/5<-3,0,4>
Two nonzero vectors u avd v are parallel if there is some scalar c
such that
u=c.v

Am I even close with this solution? I am getting more confused.

7. Feb 1, 2009

### Staff: Mentor

That's the vector you want.

8. Feb 1, 2009

Thank you.