(1/2+1/3+------+1/2009)x(1+1/2+------+1/2008)-(1+1/2+------+
(1/2+1/3+------+1/2009)x(1+1/2+------+1/2008)-(1+1/2+------+1/2009)x(1/2+1/3+------+1/2008)
赞 forture2005 幼苗
共回答了21个问题采纳率：95.2% 举报
(1/2+1/3+------+1/2009)x(1+1/2+------+1/2008)-(1+1/2+------+1/2009)x(1/2+1/3+------+1/2008)
=(1/2+1/3+------+1/2009+1-1)x(1+1/2+------+1/2008)-(1+1/2+------+1/2009)x(1/2+1/3+------+1/2008+1-1)
=(1+1/2+1/3+------+1/2009)x(1+1/2+------+1/2008) -(1+1/2+------+1/2008)-
[(1+1/2+------+1/2009)x(1+1/2+1/3+------+1/2008)-(1+1/2+------+1/2009)]
=(1+1/2+------+1/2009)-(1+1/2+------+1/2008)=1/2009
=(1/2+1/3+------+1/2009+1-1)x(1+1/2+------+1/2008)-(1+1/2+------+1/2009)x(1/2+1/3+------+1/2008+1-1)
=(1+1/2+1/3+------+1/2009)x(1+1/2+------+1/2008) -(1+1/2+------+1/2008)-
[(1+1/2+------+1/2009)x(1+1/2+1/3+------+1/2008)-(1+1/2+------+1/2009)]
=(1+1/2+------+1/2009)-(1+1/2+------+1/2008)=1/2009
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