这道题怎么做，求解
1个回答
展开全部
3n/(n^3+3n)^(1/3)≤lim(n->∞) ∑(i:1->3n) [ 1/(n^3+i)^(1/3) ] ≤ 3n/(n^3+1)^(1/3)
lim(n->∞) 3n/(n^3+3n)^(1/3)
=lim(n->∞) 3/(1+3/n^2)^(1/3)
=3
lim(n->∞) 3n/(n^3+1)^(1/3)
=lim(n->∞) 3/(1+1/n^3)^(1/3)
=3
=>
lim(n->∞) ∑(i:1->3n) [ 1/(n^3+i)^(1/3) ] =3
lim(n->∞) 3n/(n^3+3n)^(1/3)
=lim(n->∞) 3/(1+3/n^2)^(1/3)
=3
lim(n->∞) 3n/(n^3+1)^(1/3)
=lim(n->∞) 3/(1+1/n^3)^(1/3)
=3
=>
lim(n->∞) ∑(i:1->3n) [ 1/(n^3+i)^(1/3) ] =3
本回答由提问者推荐
已赞过
已踩过<
评论
收起
你对这个回答的评价是？
推荐律师服务：
若未解决您的问题，请您详细描述您的问题，通过百度律临进行免费专业咨询
