用规律计算(-1*2/1)+ (-2/1*3/1)+(-3/1*4/1)+...+(-2007/1*2008/1)

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用规律计算(-1*2/1)+ (-2/1*3/1)+(-3/1*4/1)+...+(-2007/1*2008/1)
用规律计算(-1*2/1)+ (-2/1*3/1)+(-3/1*4/1)+...+(-2007/1*2008/1)

用规律计算(-1*2/1)+ (-2/1*3/1)+(-3/1*4/1)+...+(-2007/1*2008/1)
(-1*2/1)+ (-2/1*3/1)+(-3/1*4/1)+...+(-2007/1*2008/1)
=(1/2-1)+(1/3-1/2)+(1/4-1/3)+……+(1/2008-1/2007)
=1/2-1+1/3-1/2+1/4-1/3+……+1/2008-1/2007
中间互相抵消
=-1+1/2008
=-2007/2008

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-2017036

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