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观察下列各式:-1×1/2=-1+1/2 -1/2×1/3=-1/2+1/3 -1/3×1/4=-1/3+1/4
你发现的规律是:( -1/n × 1/(n+1) = -1/n + 1/(n+1) )用含字母n的式子表示,n为正整数
(-1×1/2)+(-1/2×1/3)+(-1/3×1/4)+……(-1/2012×1/2013)
= -1+1/2-1/2+1/3-1/3+1/4-……+1/2012-1/2012+1/2013
= -1+1/2013
= - 2012/2013
1年前
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