第十题怎么做啊,跪求详细解答过程
1个回答
展开全部
比较 (2^n+1)/(3^n-1) 与 (2^n)/(3^n) 的极限情况
lim [(2^n+1)/(3^n-1)] / [(2^n)/(3^n)]
= lim [(2^n+1)/(2^n)] / [(3^n)/(3^n-1)]
因为:lim (2^n+1)/(2^n) = lim (1+1/2^n) = 1
lim (3^n)/(3^n-1) = lim 1/(1-1/3^n) = 1
所以 lim [(2^n+1)/(2^n)] / [(3^n)/(3^n-1)] = 1
这说明 (2^n+1)/(3^n-1) 与 (2^n)/(3^n) 的极限相同
又因为 lim (2^n)/(3^n) = 0
所以 lim = (2^n+1)/(3^n-1) = 0
lim [(2^n+1)/(3^n-1)] / [(2^n)/(3^n)]
= lim [(2^n+1)/(2^n)] / [(3^n)/(3^n-1)]
因为:lim (2^n+1)/(2^n) = lim (1+1/2^n) = 1
lim (3^n)/(3^n-1) = lim 1/(1-1/3^n) = 1
所以 lim [(2^n+1)/(2^n)] / [(3^n)/(3^n-1)] = 1
这说明 (2^n+1)/(3^n-1) 与 (2^n)/(3^n) 的极限相同
又因为 lim (2^n)/(3^n) = 0
所以 lim = (2^n+1)/(3^n-1) = 0
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