(-1乘2)+(-1/2乘3)+·······+(-1/2010乘1/2011)等于

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(-1乘2)+(-1/2乘3)+·······+(-1/2010乘1/2011)等于(-1乘2)+(-1/2乘3)+·······+(-1/2010乘1/2011)等于(-1乘2)+(-1/2乘3)+

(-1乘2)+(-1/2乘3)+·······+(-1/2010乘1/2011)等于
(-1乘2)+(-1/2乘3)+·······+(-1/2010乘1/2011)等于

(-1乘2)+(-1/2乘3)+·······+(-1/2010乘1/2011)等于
知识点:1/n(n+1)=1/n-1/(n+1)
原式=-(1-1/2+1/2-1/3+1/3-1/4+……+1/2010-1/2011)
=-(1-1/2011)
=-2010/2011