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Homework Help: Differentiating natural log

  1. Sep 11, 2011 #1
    1. The problem statement, all variables and given/known data

    Differentiate, f(x)=71+x/1-x

    2. Relevant equations

    3. The attempt at a solution

    Working this out, hoping it's right as I was going along, my final answer is 71+x/1-x * (2ln7)/1-x
  2. jcsd
  3. Sep 11, 2011 #2
    Check your denominator....

    Looks like you may have had a bit of a problem after you applied the chain rule. A great way to check your answers is to plug them in on www.wolframalpha.com. If you are incorrect, you can always ask us about the accuracy of your steps.
  4. Sep 11, 2011 #3

    Ray Vickson

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    Science Advisor
    Homework Helper

    Please learn to typeset expressions properly; in particular, USE PARENTHESES. Your function is f(x) = 7(1+x)/(1-x). What you wrote actually means 71 + (x/1) -x = 7.

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