1/2+1/6+1/12+1/20+1/30+1/42
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)
=1-1/7
=6/7
欢迎提问
原式=6/7
过程如下
1/2+1/6+1/12+1/20+1/30+1/42=1-1/2+1/2-1/3……+1/6-1/7=1-1/7=6/7
97分之105
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)
=1-1/7
=6/7
1/2+1/6+1/12+1/20+1/30+1/42
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)
=1-1/7
=6/7
内容全部来源于网络收集，如有侵权，请联系网站删除：QQ：24596024