Integration by parts

  • Thread starter duki
  • Start date
  • #1
264
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Homework Statement


Integrate [tex]\int{\frac{lnx}{x^4}dx}[/tex]


Homework Equations



The Attempt at a Solution



I get this:
[tex]u = ln x, du = \frac{1}{x}[/tex]
[tex]dv=x^4, v=\frac{x^5}{5}dx[/tex]
[tex]\frac{(lnx)x^5}{5}-\int{\frac{x^5}{5}*\frac{1}{x}dx} = \frac{(lnx)x^5}{5}-\frac{6x^6}{5}dx}[/tex]


Am I doing this right?
 

Answers and Replies

  • #2
726
1
Your dv should be the integral of 1/x^4, not x^4.
 
  • #3
264
0
Hmm, ok. So what would be v?
 
  • #4
726
1
The integral of x^(-4), which is 1/-3 * x^-3
 
  • #5
264
0
Oooh, ok. Thanks for your help!
 

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