simka105 Y' = ((lnx-1)'*ln^2(x)-(lnx-1)*(ln^2(x))')/ (ln^4(x)) = (1/x*ln^2(x)-2(lnx - 1)*ln(x)/x) / ln^4(x) = (ln(x) - 2(lnx - 1))/(xln^3(x))

ln(x) - 2(lnx - 1) = 0
-lnx = -1
lnx = lne
x = e