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Homework Help: Spherical wave

  1. Oct 8, 2012 #1
    Greeetings, yesterday I had to do the attached assignment but I ran into a problem. It is not so much about how to solve the exercise but rather about how to approximate the term:
    r+-r-
    My solutions notes writes this as:
    r+-r- = Lx/z0
    Is it just me or is there something wrong with this expression: How did my teacher arrive at that from:
    r+-r- = √((x-L/2)2+y2+z02) - √((x+L/2)2+y2+z02)
     

    Attached Files:

  2. jcsd
  3. Oct 8, 2012 #2
    Divide everything by Zo then use the linear approximation of the square root.
     
  4. Oct 9, 2012 #3
    hmm okay I think I got it. I just find it weird that there is no dependence on y while there is a dependence of x? Why is that intuitively?
     
  5. Oct 9, 2012 #4
    Intuitively that is because of the asymmetry along the x-axis.
     
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