Ln x dx

PrudensOptimus

Integrat Ln[x]dx!!!!

Lonewolf

Consider it as 1*ln(x) and use parts.

Tron3k

If you don't feel like doing it, you can always use:

The Integrator

It gives the answer:

[tex]
-x + x \ln x
[/tex]

himanshu121

Is [x] greatest integer function??

Lonewolf

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.

sam2

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