求1乘2,2乘3,3乘4,...,99乘100这99项的倒数的和.

问题描述:

求1乘2,2乘3,3乘4,...,99乘100这99项的倒数的和.

1/(1*2)+1/(2*3).+1/(99*100) =1-1/2+1/2-1/3+.+1/99-1/100 =1-1/100 =99/100