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Another vector proof

  1. Oct 20, 2012 #1
    1. The problem statement, all variables and given/known data
    Show that [itex] (u \times (v+w))\cdot r = (u \cdot w)(v \cdot r) - (u \cdot v)(w \cdot r) [/itex]

    2. Relevant equations

    3. The attempt at a solution
    So far I have been able to simplify the LHS to:
    [itex] (r \times u)\cdot v + (r \times u) \cdot w [/itex] but don't know how to proceed from there.

    In fact, I don't know if this problem is even solvable using only vector identities, i.e. without having to prove using components.

    All help is appreciated!

  2. jcsd
  3. Oct 20, 2012 #2


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    Hi Bipolarity! :smile:

    It's a misprint :rolleyes:

    try [itex] (u \times (v \times w))\cdot r = (u \cdot w)(v \cdot r) - (u \cdot v)(w \cdot r) [/itex] :wink:
  4. Oct 20, 2012 #3
    Thanks tiny-tim!

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