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Homework Help: Vector cross product

  1. Apr 8, 2015 #1
    1. The problem statement, all variables and given/known data
    Given a×b=-i-j+3k and c×a=2i-3j+k, find a×(a-2b+c)

    2. Relevant equations
    Cross product (DONE WITHOUT MATRICES).

    3. The attempt at a solution
    a
    ×b=c=-(b×a)is all I'm getting to at this point
     
  2. jcsd
  3. Apr 8, 2015 #2

    SammyS

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    Simply distribute the cross-product.

    ##\vec{P}\times(\vec{Q}+\vec{R})=\vec{P}\times\vec{Q}+\vec{P}\times\vec{R}##
     
  4. Apr 8, 2015 #3
    Thanks,
    so would I have to find the components of a, b, and c???
     
  5. Apr 8, 2015 #4

    SammyS

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    No. Not at all.

    What is a×a ?
     
  6. Apr 8, 2015 #5

    Dick

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    No, you only need the components of axb and axc. Follow SammyS's suggestion.
     
  7. Apr 8, 2015 #6
    Ok thanks guys I got it
     
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