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Math Help - What are the critical numbers of this?

  1. #1
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    What are the critical numbers of this?

    Hi can someone help me find the critical numbers of this function:

    f(x) = x^{8/9} - x^{17/9}

    I found the derivative to be:

    \frac{8}{9}x^{-1/9} - \frac{17}{9}x^{8/9}

    but then what?

    Thanks!
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  2. #2
    Rhymes with Orange Chris L T521's Avatar
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    Quote Originally Posted by coldfire View Post
    Hi can someone help me find the critical numbers of this function:

    f(x) = x^{8/9} - x^{17/9}

    I found the derivative to be:

    \frac{8}{9}x^{-1/9} - \frac{17}{9}x^{8/9}

    but then what?

    Thanks!
    You're almost there!

    Set f'(x)=0 and this will give you the stationary [critical] values. Also consider where f'(x) fails to exist. You will also find critical points there as well.

    --Chris
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  3. #3
    Member Nacho's Avatar
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    you must to make equal to zero the function derivative and to clear X

    P.D: the answer is \dfrac{8}{17}
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