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Math Help - an absolute max and min problem involving e

  1. #1
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    an absolute max and min problem involving e

    Find the absolute max and mins of f(x) on the given interval.

    f(x)= xe^\frac{-x^2}{8}, [-1,4]
    f'(x)= e^\frac{-x^2}{8}+\frac{-x^2}{4}e^\frac{-x^2}{8}

    e^\frac{-x^2}{8}(1-\frac{x^2}{4})^4

    e^\frac{-x^2}{8}=0

    e^\frac{-x^2}{8}=0
    =?

    (1-\frac{x^2}{4})^4=0
    (1-\frac{x^2}{4})=0
    (\frac{x^2}{4})=1

    (x^2)=4<br />

    2,-2
    Help?
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  2. #2
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    e^(whatever)=0 doesn't have any solutions.

    2 is the only solution in [-1, 4]

    So now find f(2) and also f(-1) and f(4) at the limits of the function, and compare them.
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