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Homework Help: Dot and cross product problem

  1. Sep 19, 2006 #1
    Hello, my problem is as follows:

    Given that A and B are known vectors, and
    [tex]A \cdot C=u[/tex] is a known quantity, and [tex]A \times C=B[/tex]
    Express C in terms of A,B, u, and the magnitude of A

    So far what i have done was use the definition of the dot product as AC cos [tex]\theta[/tex]=u, and cross product as AC sin [tex]\theta[/tex]=|B|, squared both and added them to get an expression for the magnitude of C squared, however i do not know how to get the vector C by itself in terms of the quantities in the question, can anyone explain how i should go about this? thanks
    Last edited: Sep 19, 2006
  2. jcsd
  3. Sep 19, 2006 #2
    I would recommend using the vector triple product and determine Ax(AxC) = AxB, expanding out the left side
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