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Homework Help: Dot product

  1. Apr 14, 2010 #1
    1. The problem statement, all variables and given/known data

    what is the dot product of [tex]G{\bullet}A[/tex] where A = [tex]\left(\frac{a_3}{l}-\frac{{a_1}}{h}\right)[/tex] and G = [tex]2{\pi}h{\frac{{a_2}}x{{a_3}}}{{a_1}{\bullet}{{a_2}}x{{a_3}}}[/tex]

    2. Relevant equations




    3. The attempt at a solution

    The answer is zero and ive got the worked solution infront of me, i just done see where the [tex]\frac{{{a_3}}}{l}[/tex] goes, the dot product of a vector with itself is 1 isnt it? but then where does the denominator go? and what about the denominator of G?
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Apr 14, 2010 #2
    sorry that first bit should say:

    G = [tex]2{\pi}h{\frac{{a_2}x{a_3}}{{a_1}{\bullet}{a_2}x{a_3}}[/tex]
     
  4. Apr 14, 2010 #3

    Mark44

    Staff: Mentor

    I replaced your formula for G by what you had in your 2nd post.
    No, the dot product of a vector is not 1 in general. u [itex]\cdot[/itex] v = |u| |v| cos([itex]\theta[\itex]).

    Speaking of vectors, which are the vectors in your problem?
     
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