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Equivalent expression for sinx^3

  1. Apr 23, 2009 #1
    1. The problem statement, all variables and given/known data
    Find an equivalent expression for sin3x in terms of function values of x, 2x, 3x, raised only to the first power.


    3. The attempt at a solution
    stuck! dont know where to begin I am reviewing for my exam right now I remember doing one of these problems before but I cant remember how.

    sinx(sinx2)

    sinx[(1-cos2x)/2]

    am i on the right track?
     
  2. jcsd
  3. Apr 24, 2009 #2

    tiny-tim

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    Homework Helper

    Hi synergix! :smile:

    (btw, don't write (sinx2), write either (sinx)2 or sin2x)

    Your equation is correct, but I don't think it's what they're asking for …

    it has a (sinx)(cos2x) … if you're allowed that, you might as well have (sinx)(sinx)(sinx).

    I think they want a sum of first powers, each on its own.

    Hint: start at the end …

    what is sin(3x) in terms of powers of sinx? :wink:
     
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