(1/2)+(1/6)+(1/12)+(1/20)+(1/30)+.+(1/420)
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/04 19:52:31
(1/2)+(1/6)+(1/12)+(1/20)+(1/30)+.+(1/420)
(1/2)+(1/6)+(1/12)+(1/20)+(1/30)+.+(1/42)
=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
再问: 请看清楚后面是什么!
再答: (1/2)+(1/6)+(1/12)+(1/20)+(1/30)+......+(1/420) =1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+......+1/20-1/21 =1-1/21 =20/21
=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
再问: 请看清楚后面是什么!
再答: (1/2)+(1/6)+(1/12)+(1/20)+(1/30)+......+(1/420) =1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+......+1/20-1/21 =1-1/21 =20/21
(1/2)+(1/6)+(1/12)+(1/20)+(1/30)+.+(1/420)
1/2+1/6+1/12+1/20+.+1/380+1/420 等于?
1/2,-1/6,1/12,-1/20,1/30
1/2+1/6+1/12+1/20+1/30
谁能告诉我求1/2+1/6+1/12+1/20+……+1/420
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
1又2\1+2又6\1+3又12\1+4又20\1+...+20又420\1
1/2+1/6+1/12+1\20+1/30+1/42+.+1/9900=?
1/2+1/6+1/12+1/20+1/30+1/42+1/56=?
1/2+1/6+1/12+1/20+1/30+1/42+1/56 简算
1/2+1/6+1/12+1/20+1/30+1/42+1/56
1+1/2+1/6+1/12+1/20+1/30+1/42的简便计算