lim(n趋向于无穷）（k/n-1/n+1-1/n+2－‘‘‘‘－1／n+k)(其中K为与N无关的正整数）_其他解答

lim(n趋向于无穷）（k/n-1/n+1-1/n+2－‘‘‘‘－1／n+k)(其中K为与N无关的正整数）

人气：209 ℃　时间：2020-09-19 22:09:31

解答

=lim(1/n-1/(n+1)+1/n-1/(n+2)+...+1/n-1/(n+k))
=lim(1/(n+1)+2/(n+2)+...+k/(n+k))/n
lim(1/(n+1)+2/(n+2)+...+k/(n+k))/n>=lim(1/(n+1)+1/(n+2)+...+1/(n+k))/n>=lim(1/(n+k)+1/(n+k)+...+1/(n+k))/n=lim k/(n(n+k))=0
lim(1/(n+1)+2/(n+2)+...+k/(n+k))/n