Question

How do I integrate (by parts)?

Answer 1

\[\int\limits_{?}^{?} (lnx)^2/(x) dx\]

Answer 2

why parts?

Answer 3

put
\[u=\ln(x), du=\frac{1}{x}dx\] and integrate
\[\int u^2du\]

Answer 4

oh i see. so when do you know to use u-substitution and when to use integration by parts?

Answer 5

i guess practice. here you see a composite function

\[(\ln(x))^2\] set beside the derivative of the inside function

\[\frac{1}{x}\] so this is a set up for a u - sub