1\2,1\3,1\4,1\5,.1\90.1\91中挑出10个数,加上正负号,使它们的和为-1

3096379482022-10-04 11:39:541条回答

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翠微江湖唯我独尊 共回答了20个问题 | 采纳率85%
-1=-1/5-1/6-1/8-1/9-1/10-1/12-1/15-1/18-1/20-1/24
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=1-1/10
所以:
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/10=1
即:
-1/2-1/6-1/12-1/20-1/30-1/42-1/56-1/72-1/90-1/10=-1
1年前

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