Expression 2: Start sum from "n" equals 1 to "i" , end sum, StartFraction, "n" Superscript, left parenthesis, "n" minus 1 , right parenthesis , Baseline Over "n" ! , EndFraction Start integral from 0 to negative ln left parenthesis, "x" , right parenthesis , end integral, "t" Superscript, left parenthesis, "n" plus 1 minus 1 , right parenthesis , Baseline "e" Superscript, negative "t" , Baseline "d" "t"i∑n=1nn−1n!∫−lnx0tn+1−1e−tdt