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分式不好打 凑合着看了
1/3+3/5+5/7+7/9+9/11+11/13
= (1-2/3)+(1-2/5)+(1-2/7)+(1-2/9)+(1-2/11)+(1-2/13)
=6-(2/3+2/5+2/7+2/9+2/11+2/13)
=6-2*(1/3+1/5+1/7+1/9+1/11+1/13)
原式=6-2*(43024/45045)
=4+4042/45045
1/3+3/5+5/7+7/9+9/11+11/13
= (1-2/3)+(1-2/5)+(1-2/7)+(1-2/9)+(1-2/11)+(1-2/13)
=6-(2/3+2/5+2/7+2/9+2/11+2/13)
=6-2*(1/3+1/5+1/7+1/9+1/11+1/13)
原式=6-2*(43024/45045)
=4+4042/45045
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