(1/8+1/24+1/48+1/80+1/120+1/168+1/224+1/228)*128
问题描述:
(1/8+1/24+1/48+1/80+1/120+1/168+1/224+1/228)*128
答
(1/8+1/24+1/48+1/80+1/120+1/168+1/224+1/288)*128
=(1/2+1/6+1/12+1/20+1/30+1/42+14/56+1/72)*32
=(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9)*32
=(1-1/9)*32
=8/9*32
=256/9