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Homework Help: Calc III

  1. Feb 1, 2009 #1
    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. jcsd
  3. Feb 1, 2009 #2
    First find a vector that goes between those 2 points
     
  4. Feb 1, 2009 #3
    Well, you know what the direction of the vector is, you just have to scale it correctly...
     
  5. Feb 1, 2009 #4
    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...
     
  6. Feb 1, 2009 #5
    What's the difference between any old vector and unit vector?
     
  7. Feb 1, 2009 #6
    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.
     
  8. Feb 1, 2009 #7

    Mark44

    Staff: Mentor

    That's the vector you want.
     
  9. Feb 1, 2009 #8
    Thank you.
     
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