# Parametric/vector equations

1. May 3, 2010

### spoc21

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

Find the vector/ and parametric equations for the line that passes through A(3, -1, 2) and parallel to the x-axis.

2. Relevant equations

N/A

3. The attempt at a solution

I know how to find the vector and parametric equations of a line, when given two points. I am just confused on what they mean by parallel to the x-axis. Would we assume the second point is (0,1,1), since it is parallel to the x-axis.. any help is appreciated.. thank you!N

2. May 3, 2010

### jtyler05si

To me that would mean the z-value is constant and also the y value. You can pick any point for x

3. May 3, 2010

### spoc21

so would the (0,1,1) work?

4. May 3, 2010

### spoc21

bump..anyone?

5. May 3, 2010

### jtyler05si

I don't believe so. Again the y and z terms would be constant.
So any value for {n} can be chosen. Your point would be (n,-1,2)

6. May 3, 2010

### Staff: Mentor

No. If you call this point B, the vector AB is not parallel to the x-axis. A vector parallel to the x-axis has a non-zero x-coordinate, and the other two coordinates are zero.

7. May 3, 2010

### spoc21

ok, so something like (1,0,0) would work? your point makes sense, just want to confirm..

8. May 3, 2010

### Staff: Mentor

Yes, the direction of the line has to be <1, 0, 0> or some scalar multiple of this vector.