I don't speak Romanian, but the closest translation for this suggests you're trying to compute
Integrate by parts:
where
u = ln(x)² ⇒ du = 2 ln(x)/x dx
dv = x³ dx ⇒ v = 1/4 x⁴
Integrate by parts again:
where
u' = ln(x) ⇒ du' = dx/x
dv' = x³ dx ⇒ v' = 1/4 x⁴
So, we have
