1/3+1/8+1/15+1/24+1/35+...+1/80+1/99 怎么解
问题描述:
1/3+1/8+1/15+1/24+1/35+...+1/80+1/99 怎么解
答
1/3+1/8+1/15+1/24+1/35+...+1/80+1/99
=1/2[(1-1/3)+(1/2-1/4)+...+(1/8-1/10)+(1/9-1/11)]
=1/2(1+1/2-1/10-1/11)
=36/55