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Cauchy/ Triangle Inequality

  1. Oct 20, 2010 #1
    I was wonder what conditions a and b have to be for each inequality in order to satifsy the equality?
  2. jcsd
  3. Oct 20, 2010 #2


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    It would help if you wrote out the inequality as a function of a and b. I'm not a mind reader.
  4. Oct 21, 2010 #3
    Cauchy's inequality is just the trivial |a . b| <= |a||b| Oo

    Triangle inequality

    |a+b| = |a| +|b|
  5. Oct 21, 2010 #4
    What do you think happens when a,b are both postive or both negative ?
  6. Oct 21, 2010 #5


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    Just go over the proof, and you'll probably see it.
  7. Oct 21, 2010 #6


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    To answer your question, you need to specify what a and b are. Possibilities: real numbers, complex numbers, vectors (either real or complex).
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