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Homework Help: Superposition problem

  1. Feb 5, 2006 #1
    The superposition of two harmonic waves:
    u1 = B * sin( a1(r) )
    u2 = B * sin( a2(r) )
    results in a sinusoidal wave of the form:
    uint = Bint * sin( a3(r) )
    Find a3 and Bint

    I'm not sure what to do. I can't think of any way to get it into that "form". http://scienceworld.wolfram.com/physics/Interference.html (5) on that link gives the form I would expect.
    I think the "int" subscript is talking about intensity, and I'm not sure but I don't think either u1 or u2 depend on time.
    Can anyone help?
     
  2. jcsd
  3. Feb 6, 2006 #2

    Meir Achuz

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    Use your high school trig (ugh).
    uint=u1+u2=B[sin(a)+sin(b)]=2B{sin[(a+b)/2]cos[(a-b)/2]}
    if I remembered it right.
     
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