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Homework Help: Law of Sines Proof

  1. Aug 1, 2009 #1
    1. The problem statement, all variables and given/known data
    Prove the law of sines using a vector cross product. (Hint, consider the area of the triangle and that A+B+C=0.)

    2. Relevant equations
    |A||C|sin ( θ ) = (a2c3 − a3c2) + (a3c1 − a1c3) + (a1c2 − a2c1)

    3. The attempt at a solution
    The farthest I went is to show .5 |a||c|sin \theta .. i've tried some other things but then it just turns out to be some incomprehensible mess. I chose C to be my longest side. I simply do not know what to do; i've exhausted both forms of the cross product I know, and it appers to go nowhere.
  2. jcsd
  3. Aug 1, 2009 #2
    Never mind, I figured it out. Thanks anyway!
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