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Homework Help: Why hello improper integral, how are you?

  1. Feb 18, 2009 #1
    1. The problem statement, all variables and given/known data
    integral from -1 to 1 of 3/x^2 dx


    2. Relevant equations



    3. The attempt at a solution
    Limit
    t --> infinity integral from -1 to t of 3/x^2 dx + limit t --> infinity integral from t to 1 of 3/x^2 dx

    Limit
    t-> infinity -3/t - (-3/-1) + Limit t--> inifinty (-3/1) - (3/t)

    -3 -3 = -6

    Now when I check the answer in my calc I get infinity. Thus my answer is probably wrong. Where did I go wrong?
    Thanks so much =]
     
  2. jcsd
  3. Feb 18, 2009 #2

    D H

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    Staff Emeritus
    Science Advisor

    Why infinity? It is (a) outside the domain, and (b) you are integrating across the singularity.
     
  4. Feb 18, 2009 #3
    This should be as t→0.
     
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