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Homework Help: Vector help

  1. Jan 31, 2012 #1

    Could someone please review my work and see if it is correct. Thanks :smile:

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

    Find two unit vectors orthogonal to both given vectors.
    i + j + k, 3i + k

    2. Relevant equations

    3. The attempt at a solution

    So I used cross product and got A x B= i+2j-3k

    Then I got magnitude: to be √ (14)

    problem asks to rationalize denominator and I eventually get..

    lower values: <-√(14)/14 i, -√(14)/7 j, 3√(14)/14 k>

    larger values: <√(14)/14 i, √(14)/7 j, -3√(14)/14 k>

    I just want to make sure that I did everything correctly.
  2. jcsd
  3. Jan 31, 2012 #2


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    Science Advisor
    Homework Helper
    Gold Member

    Looks right to me. You can verify your answers by checking that their inner (dot) products with both given vectors are zero, and that their lengths are 1.

    You really only need to check one answer because you know the second answer has to be the negative of the first.
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