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Homework Help: Wave function direction

  1. Aug 27, 2009 #1
    1. The problem statement, all variables and given/known data
    which of the wave functions describe a wave that moves in the -x direction
    y(x,t) =Asin(-kx-wt)

    2. Relevant equations
    wave function

    3. The attempt at a solution
    I know B and C both move left looking at the phase (kx+wt) because its +, however I have no idea about A. I dont know how to convert between sin and cosine or any knowledge of adding pi/2 or anything. can anyone explain this to me? Thank you
  2. jcsd
  3. Aug 27, 2009 #2


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    Science Advisor
    Homework Helper
    Gold Member

    A trig identity says sin(-x) = - sin(x). This should help.
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