试比较1-1/2+1/3-1/4+……-1/1998+1/1999和1/1000+1/1001+……+1/1999的大小

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试比较1-1/2+1/3-1/4+……-1/1998+1/1999和1/1000+1/1001+……+1/1999的大小

1-1/2+1/3-1/4+……+1/1997-1/1998+1/1999
=(1+1/2+1/3+1/4+……+1/1997+1/1998+1/1999)-2(1/2+1/4+……+1/1998)
=(1+1/2+1/3+1/4+……+1/1997+1/1998+1/1999)-(1+1/2+……+1/999)
=1/1000+1/1001+……+1/1998+1/1999
所以1-1/2+1/3-1/4+……+1/1997-1/1998+1/1999=1/1000+1/1001+……+1/1998+1/1999