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Homework Help: *Vector Algebra*

  1. Jun 16, 2008 #1
    1. The problem statement, all variables and given/known data

    a(v), b(v) and c(v) are three vectors. if a(v) x b(v) = c(v) and b(v) x c(v)= a(v)
    Show that b(mod)= 1 and a(mod)=c(mod) and the three vectors are mutually perpendicular.
    (v) denotes vector and (mod) denotes magnitude.
    2. Relevant equations[/]


    3. The attempt at a solution

    Got some of it.Need a bit more explanation.
  2. jcsd
  3. Jun 16, 2008 #2


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    Homework Helper

    To show that they are perpendicular, you need to show that [tex]\vec{a} \cdot \vec{b} = 0[/tex], since you already know that vector c is perpendicular to both a and b. See if you can apply this to what you are given.

    As for the other two, one follows from the other. Just use the formula for magnitude of vector product on both given vector equations and compare them.

    This should help:
  4. Jun 17, 2008 #3
    Thanks bro.How did ya know if c was perpendicular to both?
  5. Jun 17, 2008 #4
    because C is the cross product of A and B, hence it must be perpendicular to both vectors.
  6. Jun 18, 2008 #5
    Thanks lord.I missed such a silly thing.
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