1楼WaterIceFlower
(......)
发表于 2007-9-30 19:42
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原式
=1/2(1/1x2-1/2x3)-1/2(1/2x3-1/3x4)-1/2(1/3x4-1/4x5)-......1/2(1/98x99-1/99x100)
=1/2[(1/1x2-1/2x3)-(1/2x3-1/3x4)-(1/3x4-1/4x5)-......(1/98x99-1/99x100)]
=1/2[1/1x2-1/2x3-1/2x3+1/3x4-1/3x4+1/4x5-......-1/98x99+1/99x100]
=1/2[1/2-1/3+1/99x100]
=1/2(1/6+1/99x100)=(1/2)x(1651/9900)=1651/19800
不知道算得对否？
[ 本帖最后由 WaterIceFlower 于 2007-9-30 19:45 编辑 ].
