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Math Help - Differentiate (ln x)^3

  1. #1
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    Post Differentiate (ln x)^3

    The problem I am having is that ln x is all cubed and i dont know how to attack this problem properly. So this is not equal to ln x^3 which would differentiate to 3 ln x. So Thanks Looking forward for a reply.
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  2. #2
    Mtl
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    well you would take the 3(from the exponent) and multiply it with the original function to 1 less exponent. And then multiply this by the derivitive of lnx...

    So it would look like 3((lnx)^2)(1/x)
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  3. #3
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    First use the chain rule to get:

    \tfrac{d}{dx}(\ln x)^3 = 3(\ln x)^2 \cdot \tfrac{d}{dx}\ln x

    Then you should be able to derivate the ln x and get your answer.

    Think of these questions like an onion. You have to peel away the outside of them before you can derivate what's inside the brackets.
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