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Homework Help: Integration prob

  1. Nov 5, 2009 #1
    1. The problem statement, all variables and given/known data

    Integrate [tex]\int \frac{1}{x}[/tex] dx

    2. Relevant equations

    3. The attempt at a solution
    using formula of integration what i got is [tex]\frac{1}{0}[/tex]
    which is infinity wth
  2. jcsd
  3. Nov 5, 2009 #2


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    Homework Helper

    Hi look416! :smile:
    But what are the limits of integration?

    (and the integral of 1/x is logx :wink:)
  4. Nov 5, 2009 #3
    ops for got to put
    the limits are e < x < 1
  5. Nov 5, 2009 #4


    Staff: Mentor

    It's not true that e < 1, so you can't have e < x < 1. The limits of integration are x = 1 and x = e, most likely, with the lower limit of integration being x = 1. If you have them in the other order you'll get a negative value for the integral.
  6. Nov 5, 2009 #5
    very sorry
    just rechecked the question yep
    its 1 < x < e
    but still i have no idea to integrate it
  7. Nov 5, 2009 #6


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    Do you know any result/formula which could help you calculate [itex] \int_{1}^{e} \frac{1}{x} \ {} dx [/itex] ?
  8. Nov 5, 2009 #7
    I think OP needs to review basic definition of integration of f(x)=1/x. It does not follow the "power rule" that he has inadvertly applied.
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