please send the detailed solution. In this problem Reiman’s sum concept is used and I don’t know about it.

lnL =   lim  (1/n).[ln(1 + 1/n) + ln(1 + 2/n) +...+ ln(1 + n/n)]

          n

 

Now use expansion of ln(1 + x) which is x – x²/2 + x³/3 – … and neglect higher powers of x here as n is tending to infinity.