除以1×2的积+1除以2×3的积加1除以3×4的积=四分之三,那么1除以n×(n+1)等于多少

2025-04-19 14:59:33
推荐回答(1个)
回答1:

1/(1*2)+1*(2*3)+1/(3*4)
=1-1/2+1/2-1/3+1/3-1/4
=1-1/4
=3/4

1/[n(n+1)]
=1/n-1/(n+1)