How to integrate Ln x dx

  • #1
Integrat Ln[x]dx!!!!
 

Answers and Replies

  • #2
334
1
Consider it as 1*ln(x) and use parts.
 
  • #3
45
0
If you don't feel like doing it, you can always use:

The Integrator

It gives the answer:

[tex]
-x + x \ln x
[/tex]
 
  • #4
650
1
Is [x] greatest integer function??
 
  • #5
334
1
Hmm, didn't consider that. I'm not sure there'd be a closed form expression for [itex]\int ln[x] dx [/itex]
where [itex][x][/itex] is the next greatest integer function. It'd be easy enough to get a numerical answer if the interval was specified though.
 
Last edited:
  • #6
22
0
You could break the integral into a summation. [x] is constant between intervals of integers, so you end up with a sum of trivial integrals.

I think this is what Lonewolf is proposing (please excuse my ignorance!)

Regards,
Sam
 

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