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Find max/min within what we've been taught?

  1. Feb 15, 2005 #1
    Hi,

    I have the function [tex] 0.1x^3 - 3x[/tex] and I would like to find its local maxima and minima within the domain of [-10,10]. The problem is I don't think we've been taught a way yet; I'm currently in Calculus I and just before derivatives. Is there a way within my current knowledge to find the fraction representing the max and min of this function within the above domain?
     
  2. jcsd
  3. Feb 15, 2005 #2
    I would think that the local max and min could be approximated by taking the midpoint x value between roots. Edit: Have you been taught limit notation yet?
     
  4. Feb 15, 2005 #3

    dextercioby

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    Can't u use a computer & graph it...?

    Daniel.
     
  5. Feb 15, 2005 #4
    Yeah we've been taught limit notation. And we can probably just give the value 3.1622... but I'm trying to be as thorough as possible.

    We have roots
    [tex]\sqrt{1.2}/1.2
    and
    0[/tex]
    The midpoint isn't the max/min cause the function isn't linear (i think thats why).
     
  6. Feb 15, 2005 #5

    dextercioby

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    Unfortunately u can find the exact (x,y) values or the extrem through calculus.Approximate values can be achived by plotting...It has 3 roots,BTW

    Daniel.
     
  7. Feb 15, 2005 #6
    If you know limit notation I think you can cheat and use the definition of a derivative.
     
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