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Homework Help: Parametric/vector equations

  1. May 3, 2010 #1
    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


    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. jcsd
  3. May 3, 2010 #2
    To me that would mean the z-value is constant and also the y value. You can pick any point for x
  4. May 3, 2010 #3
    so would the (0,1,1) work?
  5. May 3, 2010 #4
  6. May 3, 2010 #5
    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)
  7. May 3, 2010 #6


    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.
  8. May 3, 2010 #7
    ok, so something like (1,0,0) would work? your point makes sense, just want to confirm..
  9. May 3, 2010 #8


    Staff: Mentor

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