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Homework Help: Differentiation Problem?

  1. Mar 3, 2008 #1
    simple SIMPLE local extremia question

    1. The problem statement, all variables and given/known data

    Find the absolute maximum and absolute minimum values of f(x) = 3x^4 - 8x ^3 + 12x^2 -48x +25, where 0 <= x <= 3.


    2. Relevant equations

    N/a

    3. The attempt at a solution

    f'(x) = 12x^3 - 24x^2 + 24x -48
    = 12 (x^3 - 2x^2 + 2x -4)
    = 12 (x-2) (X^2 +2)

    I know how to do the rest, but just wondering before I go on... What should i do with that one factor...do I omit the (x^2 +2)?
     
    Last edited: Mar 3, 2008
  2. jcsd
  3. Mar 3, 2008 #2
    Well beside your first three lines of solution being irrelevant, it looks correct to me.

    Edit: Actually you forgot a factor of 2 in your final h solution according to the symbolic result you derived earlier on.
     
  4. Mar 3, 2008 #3
    Okay thanks alot, I updated the thread with a different question lol
     
  5. Mar 3, 2008 #4
    Well you know that the absolute maximum/minimum lies at a place where the derivative is 0 or at the endpoints of the interval. Does x^2+2=0 have a real solution?
     
  6. Mar 3, 2008 #5
    haha...thanks man. I'm starting to forget to most simple stuff
     
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