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Homework Help: Prove that this vector is equal to this?

  1. Apr 27, 2010 #1
    1. The problem statement, all variables and given/known data
    Prove that |[tex]\vec{A}[/tex]|2+|[tex]\vec{B}[/tex]|2 equals to [tex]\frac{1}{2}[/tex](|[tex]\vec{A}[/tex]+[tex]\vec {B}[/tex]|2+|[tex]\vec{A}[/tex]-[tex]\vec{B}[/tex]|2)

    2. Relevant equations
    Perhaps the triangle inequality? I am not sure.

    3. The attempt at a solution
    I have no idea how to approach this question. Please help me with clear explanations. Thank you.
  2. jcsd
  3. Apr 27, 2010 #2


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    Last edited by a moderator: Apr 25, 2017
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