1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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
    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

    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

    User Avatar
    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.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook