发布网友 发布时间:2024-10-23 23:56
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热心网友 时间:2024-11-07 03:31
裂项法: 1又1/3-7/12+9/20-11/30+13/42-15/56+17/72 =1+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+1/9 =1又1/9