I have tried using the integration by parts method, with 3 terms: $\int l' m n = lmn - \int l m' n - \int lm n'$.
I put $l′= e^{-jwt}$, $m = sin (at)$ and $n = \frac{1}{t}$.
Meaning $l = \frac{-e^{-jwt}}{jw}$, $m′ = acos (at)$ and $n' = \frac{-1}{t^2}$.
I don't seem to be getting the correct answer though. What am I doing wrong?
P.S. My first time on this site, sorry if I posted something in the wrong way.