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Homework Help: This is the correct Derivative?

  1. Nov 4, 2012 #1
    1. The problem statement, all variables and given/known data

    Need to find the derivative:

    y=logx/2-logx=logx*(2-log(x))^-1

    3. The attempt at a solution

    The derivative of log(x) is 1/xln(10) and the derivative of (2-log(x))^-1 is -(2-log(x))^-2*1/xln(10)?

    This ended as

    1/xln(10)(2-logx) - logx/xln(10)(2-log(x))^2

    2-log(x)-log(x)/xln(10)(2-log(x))^2


    Though the answer is 2/xln(10)(2-log(x))^2... so what am I doing wrong?
     
  2. jcsd
  3. Nov 4, 2012 #2

    mfb

    User Avatar
    2017 Award

    Staff: Mentor

    In general, more brackets and/or spaces would help. TeX syntax is even better: ##\frac{\log(x)}{x}##.

    I think you are missing ^(-1) in the first part and a minus sign in the second part. I don't see how the following line follows from that expression.
    The answer is missing a minus, too?
     
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