简便计算:1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
答案:4 悬赏:60
解决时间 2021-03-14 09:25
- 提问者网友：柠檬香
- 2021-03-13 19:33
各位帮帮忙，我快交作业了
最佳答案
- 二级知识专家网友：你把微笑给了谁
- 2021-03-13 21:02
1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
=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+1/9-1/10
=2-1/10
=1.9
=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+1/9-1/10
=2-1/10
=1.9
全部回答
- 1楼网友：抱不住太阳的深海
- 2021-03-13 23:29
1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
=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+1/9-1/10
=2-1/10
=1.9
好久没有做这种数学题了
- 2楼网友：两不相欠
- 2021-03-13 22:55
1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
=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+1/9-1/10
=1+1/2+1/2-1/10
=1又9/10
- 3楼网友：一只傻青衣
- 2021-03-13 22:39
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
=1/2+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+……+（1/9-1/10)
=1-1/10
=9/10
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