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Homework Help: Simplifying an expression

  1. Mar 11, 2004 #1
    can someone explain to me the stages that are missing in the expression in the attached picture. i think that it has to do with identities but in the book that i got it from did not explain clearly how they went from one line to another. i will appreciate the help very much.

    Attached Files:

  2. jcsd
  3. Mar 11, 2004 #2
    It uses this identity:

    [tex]sin(x)cos(y) = \frac{1}{2}\left(sin(x+y) + sin(x-y)\right)[/tex]

    [tex] x = \theta[/tex]
    [tex] y = \theta - 30^o[/tex]
  4. Mar 11, 2004 #3
    thanx very much gnome i thought that i would never get a response
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