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Homework Help: Vector Subtraction

  1. Nov 9, 2005 #1
    How can I find the norm of [itex](\vec{v} - \vec{w})[/itex] without using [tex]||\vec{v} - \vec{w}||^2 = ||\vec{v}||^2 + ||\vec{w}||^2 - 2 ||\vec{v}|| \cdot ||\vec{w}|| \cos \theta[/tex]?
    Last edited: Nov 9, 2005
  2. jcsd
  3. Nov 12, 2005 #2
    Do you know the components of these vectors ?
    Do you have a base in which you can write them down ?

    Do not say NO, because you must have this:wink:
  4. Nov 13, 2005 #3
    I know that the terminal point of the two vectors are v = (1, 6, 2) and w = (3, 1, 7)
  5. Nov 13, 2005 #4
    Well then, in components the subtraction is just [tex](a,b,c) - (a',b',c') = (a-a', b-b', c-c')[/tex] and the magnitude of a vector with components a, b and c is [tex]\sqrt {a^2 + b^2 + c^2}[/tex]

    So you have everything to calculate the norm of a vector with given components.


  6. Nov 13, 2005 #5
    Thanks a lot!
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