What is the antiderivative of $lnx$ ?

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Answer 1 · 2018-03-16T21:07:52

$intlnxdx=x(lnx-1)+"c"$

To find an antiderivative of $lnx$ , we must find $intlnxdx$ . To do so, we use integration by parts.

$intudv=uv-intvdu$

Let $u=lnx rArr du=1/xdx$

And $dv=dx rArr v=x$

So

$intlnxdx=xlnx-intdx=xlnx-x=x(lnx-1)$

What is the antiderivative of lnxlnx?