lim(n→∞)[(n+3)/(n+1)]^n
=lim(n→∞){[1+2/(n+1)]^(n+1)}/[1+2/(n+1)]
=lim(n→∞){[1+2/(n+1)]^(n+1)/2}^2/lim(n→∞)[1+2/(n+1)]
={lim[(n+1)/2→∞][1+2/(n+1)]^(n+1)/2}^2/(1+0)
=e^2/1
=e^2.
lim(n→∞)[(n+3)/(n+1)]^n
=lim(n→∞){[1+2/(n+1)]^(n+1)}/[1+2/(n+1)]
=lim(n→∞){[1+2/(n+1)]^(n+1)/2}^2/lim(n→∞)[1+2/(n+1)]
={lim[(n+1)/2→∞][1+2/(n+1)]^(n+1)/2}^2/(1+0)
=e^2/1
=e^2.