问题标题:
【1+12+34+78+1516+3132+6364+127128】
问题描述:
1+12+34+78+1516+3132+6364+127128
宋建军回答:
1+12+34+78+1516+3132+6364+127128
=1×8-(1/2+1/4+1/8+...+1/128)
=8-1/2(1-(1/2)^7)/(1-1/2)
=8-1+(1/2)^7
=7+(1/2)^7
=7又1/128
点击显示
数学推荐
热门数学推荐