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Is <-x,-x> = <x,x> ?

  1. Sep 2, 2008 #1
    Is <-x,-x> = <x,x> !!!!!!?

    Thanks!
     
  2. jcsd
  3. Sep 2, 2008 #2

    HallsofIvy

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    Re: Is <-x,-x> = <x,x> !!!!!!?

    That depends on what you mean by <x, x>!

    Some people use it to mean a 2 vector. In that case, <-x, -x>= <x, x> only if x= 0. Other wise, <-x, -x>= -<x, x>.

    But you may be referring to an inner product in some vector space. If that is so, then <-x, -x>= -< x, -x> = -(-<x, x>)= <x, x> so that is, in fact, true.
     
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