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Homework Help: Given Vector, Find Unit Vector

  1. Jan 29, 2010 #1
    1. The problem statement, all variables and given/known data
    Given vector v = <3, -4>, find a unit vector u in the direction of vector v. Give your answer for u as
    u = <a, b>
    u = ai + bj

    2. Relevant equations


    3. The attempt at a solution

    Would I use y2-y1 and x2-x1?
  2. jcsd
  3. Jan 29, 2010 #2


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    Gold Member

    Do you know how to find the length of a vector? If so, use the fact that any vector divided by its length will have a length of 1 (i.e., it will be a unit vector).
  4. Jan 29, 2010 #3
    A unit vector is given by a vector divided by its magnitude. To find a vector's magnitude, or length, use v=sqrt[x^2+y+2].
  5. Jan 29, 2010 #4
    OK, so I got the magnitude of the vector to be 5. So does that mean the answer would be 3/5 i - 4/5 j and <3/5 , -4/5>
  6. Jan 29, 2010 #5
    That's it!
  7. Jan 29, 2010 #6
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