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Trig identity

  1. Sep 16, 2005 #1
    no clue how to start this:

    show

    sin 3x = 3 sin x - 4 sin^3 x
     
  2. jcsd
  3. Sep 16, 2005 #2
    How to start this: sin(3x) = sin(2x+x)
     
  4. Sep 16, 2005 #3
    right so after doing this i get

    sin 3x = sin2x(cos x) + (cos2x)(sin x)

    whats next
     
  5. Sep 16, 2005 #4
    sin(2x)=...?
    cos(2x)=...?
     
  6. Sep 16, 2005 #5
    thanks for the help i got this and the others
     
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