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Homework Help: Derivative of a function, Is my answer correct?

  1. Oct 25, 2009 #1
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Oct 25, 2009 #2
    [Edit] I didn't catch the missing 9; sorry about that.
    Last edited: Oct 25, 2009
  4. Oct 25, 2009 #3


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    is that (using t for theta)

    y=e^(9t.sin(8t)) or y=(e^(9t)).sin(8t)?
  5. Oct 25, 2009 #4
    Ugh, it said incorrect...
  6. Oct 25, 2009 #5


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    if it is

    i think you should get an extra factor of 9
    y'=(e^(9t)).(9sin(8t)+ 8cos(8t))
  7. Oct 25, 2009 #6


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    Gold Member

    Lanedance is right, you get that factor of 9 when taking the exponential derivative.
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