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Double modulus sign?

  1. Apr 1, 2012 #1
    I'm confused regarding why the double modulus sign is used. Let's take the dot product:

    u.v=|u||v|cosθ The R>H>S means that the cosine of the angle is multiplied witht the magnitudes of both vectors.
    Does this mean the same thing? Help?
  2. jcsd
  3. Apr 1, 2012 #2


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    Science Advisor

    Typically when you see ||a|| it refers to a norm or length of a vector just for future reference. In this case it means the same thing, but in other contexts it may not.

    Whenever you look at geometry and you see ||a||, then this will refer to norms and if people need to refer to distance and the space is a norm then this will be used.
  4. Apr 1, 2012 #3
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