级数求和∑1⼀n(n+1) (高数问题) n取1到 无穷,求解思路

2025-05-05 07:41:16
推荐回答(4个)
回答1:

回答2:

∑1/n(n+1) = 1/(1*2) + 1/(2*3) + 1/(3*4) + .... + 1/(n(n+1))
= (1/1 - 1/2) + (1/2 - 1/3) + (1/3 - 1/4) + .... + (1/n - 1/(n+1) )
去掉括号,除了第一项和最后一项抵消
= 1 - 1/(n+1)
n->∞, 1/(n+1) ->0
lim(n->∞) ∑1/n(n+1) = 1

回答3:

回答4: