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Homework Help: Simple (?) Integral

  1. Sep 21, 2008 #1

    The integral of ((1-x)/x^2)dx is: -(1/x) + ln(x) + c
    Is that correct?

    Mathematica is giving some strange answer containing a log.
  2. jcsd
  3. Sep 21, 2008 #2


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    Homework Helper

    +ln(x) should be -ln(x)
  4. Sep 21, 2008 #3
    sorry, yes thats what i meant!
  5. Sep 21, 2008 #4


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    Homework Helper

    then it should be correct providing that you remember to change the + to a -.
  6. Sep 21, 2008 #5


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    Almost. (1-x)/x2= 1/x2- 1/x and the integral of that is -1/x- ln(x)+ c

    ??YOUR answer contains a log! What was the strange answer Mathematica gave? If you mean that Mathematica is giving an answer with a logarithm base 10, perhaps it is using the fact that ln(x)= log(x)/log(e) where "log" is logarithm base 10. If it is just giving -1/x- log(x)+ c, then it is using "log" to mean natural logarithm. That is fairly standard now where common logarithms are not much used.
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