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Homework Help: How do I define a sine wave?

  1. Jul 26, 2005 #1
    Dear All,

    I have an apparatus that produces a graph of results that looks to me like a sine wave (a half wave plate affecting the power throughput of a laser; it goes from maximum to minimum 4x throughout its 360º rotation). My problem is that I need to define this line as a formula but have no idea where to start. Any ideas, anyone?
     
  2. jcsd
  3. Jul 26, 2005 #2

    quasar987

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    You look at the amplitude A (maximum height) of the wave. You also find the period T on the x axis and if the wave is out of phase, you find the distance d from the origin of how much it is out of phase in the direction of positive x. Then the equation is

    [tex]y(x) = Asin \left(\frac{2\pi (x-d)}{T}\right)[/tex]
     
  4. Jul 26, 2005 #3
    Thanks, Quasar987!
     
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