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Homework Help: Integration (iii)

  1. Dec 15, 2009 #1
    integration of x / ((x+1)^4)
    i cant use integration by subs..
    partial fraction will consume time to answer this question..
    which integration method should i use?
     
  2. jcsd
  3. Dec 15, 2009 #2

    rock.freak667

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    Homework Helper

    Try substitution instead, u=x+1
     
  4. Dec 15, 2009 #3
    ok.. when u = x + 1 ; du = 1 dx

    i should get du = x dx first..
    but subs method didnt work..
     
  5. Dec 15, 2009 #4
    Have faith, because it should work. If it still doesn't for you, post your work here.
     
  6. Dec 15, 2009 #5
    You don't need to get du=xdx. rockfreak's suggestion works fine, just try it. Alternatively you could do a partial integration.
     
  7. Dec 15, 2009 #6
    got it!!!
    (-1/2)(x+1)^-2 + (1/3)(x+1)^-3 + C.

    what if i got x^2 / ((x+1)^4)
     
  8. Dec 15, 2009 #7
    The same trick works. You should try it.
     
  9. Dec 15, 2009 #8
    got it!! thanks guys!! =)
     
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