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Homework Help: Need help Determining the Derivative

  1. Sep 24, 2011 #1
    f(x)= -3x^4/(4x-8)^(1/2),

    f'(x)=?

    Cannot figure out how to do this one, would appreciate help finding my mistakes!


    I'm sure you all cna find the answer yourself but for convenience it is -3x^3(7x-16)/(4(x-2)^(3/2))
     

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    Last edited: Sep 24, 2011
  2. jcsd
  3. Sep 24, 2011 #2

    gb7nash

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    Homework Helper

    Your answer is right, but we need to somehow get x-2 instead of 4x-8:

    At the step:

    [tex]\frac{(4x-8)(-12x^3) +6x^4}{(4x-8)^{\frac{1}{2}}(4x-8)}[/tex]

    We can factor a number out of (4x-8)1/2. We can also factor a number out of (4x-8). Once you get to the last step of your work, you can factor out a number from (14x-32).
     
  4. Sep 24, 2011 #3
    i got it! thanks a lot i just didn't see the equivalency thanks!
     
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