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Homework Help: Vectors question help

  1. Mar 6, 2014 #1
    1. The problem statement, all variables and given/known data
    If two linearly independent vectors are of equal magnitude, prove that their sum is perpendicular to their difference.

    2. Relevant equations
    v1.v2 = 0

    3. The attempt at a solution
    This question doesn't seem that hard but it's really confused me.
    Help is appreciated, thanks.
  2. jcsd
  3. Mar 6, 2014 #2


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    Science Advisor
    Gold Member
    2017 Award

    Just write down the scalar product!
  4. Mar 6, 2014 #3


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    Science Advisor

    This is a "relevant equation" only if you say what v1 and v2 are! In particular are you clear that v1 and v2 are NOT the "two linearly independent vectors" of the question? Call the two vectors u and v. Their sum is u+ v and their difference is u- v. So "their sum is perpendicular to their difference" means (u+ v).(u- v)= 0. What does the fact that they are linearly independent tell you?

  5. Mar 6, 2014 #4


    Staff: Mentor

    noahsdev, per Physics Forums rules, you must show what you have tried when you post a question.
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