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Math Help - f(x)=x*ln(x-2)

  1. #1
    MHF Contributor Also sprach Zarathustra's Avatar
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    f(x)=x*ln(x-2)

    Find the intersection points with the axis of following function:

    f(x)=xln(x-2)

    Notice please that the roots are 0 and 3

    BUT the function is not defined there!

    What is the explanation for that?
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  2. #2
    MHF Contributor matheagle's Avatar
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    the domain is x>2, so 3 is ok.
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  3. #3
    MHF Contributor Also sprach Zarathustra's Avatar
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    Ok! I've got it...(My foolish mistake!!!)

    Sorry, and thank you!
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  4. #4
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    What makes you believe that x is a root?

    (If it were f(x)= xln|x-3| then the roots would be x= 3 and x= 0.)
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  5. #5
    MHF Contributor Also sprach Zarathustra's Avatar
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    Quote Originally Posted by HallsofIvy View Post
    What makes you believe that x is a root?

    (If it were f(x)= xln|x-3|(you mean xln|x-2|?then the roots would be x= 3 and x= 0.)
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