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Math Help - Find the derivative of: (1-x)*ln(1-x)

  1. #1
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    Find the derivative of: (1-x)*ln(1-x)

    y = (1-x)*ln(1-x) has a line att Xminimum. What is the equation of the line in exakt form?

    Hint was: Find the x' and x'':

    Thanks in advance Henry from Sweden
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  2. #2
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    Quote Originally Posted by Henryt999 View Post
    y = (1-x)*ln(1-x) has a line att Xminimum. What is the equation of the line in exakt form?

    Hint was: Find the x' and x'':

    Thanks in advance Henry from Sweden
    Henry ... you need to post these calculus questions in the calculus forum, not precalculus.


    w/r to your derivative ...

    y = (1-x) \cdot \ln(1-x)

    use the product rule ...

    y' = (1-x) \cdot \left(\frac{-1}{1-x} \right) + \ln(1-x) \cdot (-1)

    y' = -[1 + \ln(1-x)]

    y'' = \frac{1}{1-x}

    I'm not really sure about your request for the equation of a line?
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  3. #3
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    Sorry for posting in the wrong forum.
    But thank you for your advice. The question about the line was:
    Fint the linear equation of the tangent in: Xminimum
    But thanks to your advice it was easy.
    Thank you, with kind regards
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