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Math Help - Stuck with a problem involving ln and abs. value..

  1. #1
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    Stuck with a problem involving ln and abs. value..

    Let f be the function defined by f(x)=ln(|x/(1+x^2)|)

    I'm stuck with how I'm supposed to find the derivative of that..
    I know the derivative of f(x)=lnx, but the absolute value throws me off.

    I know. It's a silly thing to be stuck on.
    Someone please help.
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  2. #2
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    \ln\left|\frac{x}{x^2+1}\right| = \ln|x| + \ln(x^2+1)<br />
    derivative is \frac{1}{x} + \frac{2x}{x^2+1}

    all the absolute value does is extend the domain to include negative values of x.
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