1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    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!

Please confirm the answer for this integral

  1. Sep 22, 2007 #1
    Can anyone confirm that the answer
    for int (1/x(x-1))dx


    - ln|x|+ ln |x-1| + c using partial fractions?

    Thank you.
  2. jcsd
  3. Sep 22, 2007 #2


    User Avatar

    Staff: Mentor

    How about expanding [tex]\frac{1}{x (x-1)}[/tex] into

    [tex] \frac{A}{x}\,+\,\frac{B}{x-1}[/tex] and solve for A and B

    then solve the integral
  4. Sep 22, 2007 #3


    User Avatar
    Staff Emeritus
    Science Advisor

    Can't you "confirm" it yourself by differentiating? The derivative of -ln |x|+ ln|x-1|+ c
    (assuming for the moment that x> 1 so both x and x-1 are positive) is -1/x+ 1/(x-1)= -(x-1)/(x(x-1))+ x/(x(x-1))= 1(x(x-1)). (You might want to combine those two logarithms.)

    I suspect that is exactly what he did! Doing it again is not a "check".
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Please confirm the answer for this integral