so sánh : A = 2008 / 2009 + 2009 / 2010 + 2010 / 2011 B = 2008 + 2009 + 2010 —————————-

0 bình luận về “so sánh : A = 2008 / 2009 + 2009 / 2010 + 2010 / 2011 B = 2008 + 2009 + 2010 —————————-”

1. Đáp án + Giải thích các bước giải:

   `A=2008/2009+2009/2010+2010/2011>2008/2011+2009/2011+2010/2011=(2008+2009+2010)/2011>(2008+2009+2010)/(2009+2010+2011)=B`

   Vậy `A>B`

    

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2. Đáp án:

    `A>B`

   Giải thích các bước giải:

   ta có :

   `A=2008/2009+2009/2010+2010/2011`

   `B=(2008+2009+2010)/(2009+2010+2011)`

   `=2008/(2009+2010+2011)+2009/(2009+2010+2011)+2010/(2009+2010+2011)`

   ta xét :

   `=>` `2008/2009>2008/(2009+2010+2011)`

   `=>` `2009/2010>2009/(2009+2010+2011)`

   `=>` `2010/2011>2010/(2009+2010+2011)`

   nên : `2008/2009+2009/2010+2010/2011>(2008+2009+2010)/(2009+2010+2011)` 

   `=>` `A>B`

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