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Cross product imaginary numbers

  1. Oct 10, 2015 #1

    I was just wondering if you have a cross product can you multiply out the constants and put them to one side.

    So ik x ik x E is equal to i^2(k x k x E) therefore is equal to -k x k x E.

    Is that correct?
  2. jcsd
  3. Oct 10, 2015 #2


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    Yes, the cross product is linear. However, writing something like A x B x C is not well defined as the cross product is not associative. You have to write either A x ( B x C) or (A x B) x C. Generally (k x k) x E = 0 while k x (k x E) will be non-zero if k and E are not parallel.
  4. Oct 10, 2015 #3
    Ahhhh yes the brackets! Thank You!!!
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