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Homework Help: Wave function

  1. Apr 21, 2007 #1
    In my text
    y(x,t)=Acos(kx-ω t)
    In the teacher's handout:
    y(x,t)=Asin(kx-ω t)
    There's a translational difference of pi/2 between them! I don't know which one to use for the test :S
  2. jcsd
  3. Apr 22, 2007 #2
    hehe, its just a matter of initial condition (with difference of pi)
    and thereotically an ideal sound wave is usually calculated for a stablized value which means the initial condition doesnt matter much.. very seldom do we need to know its initial condition..
    so no matter sin or cos will end up with e same results.
    and u can use either one u want due to different kinds of calculations
  4. Apr 22, 2007 #3


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    To be accurate, there's a translational difference of pi/2k between them.

    Or looking at it a different way, there is a time difference ot pi/2ω

    As zergju says, they both represent "the same wave motion", but measured relative to differet points in space and/or time.
  5. Apr 22, 2007 #4
    That was helpful, thanks
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