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Definite integration

  1. Aug 10, 2007 #1
    1. The problem statement, all variables and given/known data
    integration 9_0 c/x^3 dx. the answer is (3/8)c.


    2. Relevant equations
    just distrib. then plug in the #'s


    3. The attempt at a solution
    =cx^-3
    = (cx^-2)/-2=c/-2x^2
    I know it has something to do with distribution.
     
    Last edited: Aug 10, 2007
  2. jcsd
  3. Aug 10, 2007 #2

    G01

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    I assume your problem statement is supposed to represent this(please confirm):

    [tex]\int^9_0 \frac{c}{x^3}dx[/tex]

    If this is the case, I agree with your answer. When I evaluate the integral at the bounds I do not get the answer you stated. I get -c/162 as an answer. Are you sure that is correct?
     
    Last edited: Aug 10, 2007
  4. Aug 10, 2007 #3
    My apologies, it is 2_1 not 9_0
     
  5. Aug 10, 2007 #4

    G01

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    Ahh if that is the case, then I do get (3/8)c as the answer. Were the bounds your problem, or is there something else?
     
  6. Aug 10, 2007 #5
    that was pretty much it. did u put x^3 on top? or did you left the x^3 on the bottom? Because i believe that was my problem on this one.
     
  7. Aug 10, 2007 #6

    G01

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    I think it is good practice to write any fraction of c/x^n as cx^-n. I think it makes many problems look less complicated. So, yes, if this is what you mean, I did "put the x^3 on top."
     
  8. Aug 10, 2007 #7
    ok i got it now. thanx
     
  9. Aug 10, 2007 #8

    G01

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    Your Welcome!
     
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