2, 1/1×2 + 1/2×3 + 1/ 3×4 +…+1/2004×2005 + 1/2005×2006 1 tym + ctrlhn + 5*

Question

2,
1/1×2 + 1/2×3 + 1/ 3×4 +…+1/2004×2005 + 1/2005×2006
1 tym + ctrlhn + 5*

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Lydia 2 tháng 2021-10-13T17:59:25+00:00 2 Answers 7 views 0

Answers ( )

    0
    2021-10-13T18:01:00+00:00

    1/1×2 + 1/2×3 + 1/ 3×4 +…+1/2004×2005 + 1/2005×2006

    =1-$\frac{1}{2}$ + $\frac{1}{2}$ -$\frac{1}{3}$+$\frac{1}{3}$-$\frac{1}{4}$+$\frac{1}{4}$- $\frac{1}{5}$+…+$\frac{1}{2005}$-$\frac{1}{2006}$

    =1-$\frac{1}{2006}$ =$\frac{2005}{2006}$ 

     

    0
    2021-10-13T18:01:11+00:00

    Đáp án:

     

    Giải thích các bước giải:

    `1/1.2+1/2.3+1/3.4+….+1/2004.2005+1/2005.2006`

    `=1-1/2+1/2-1/3+1/3-1/4+….+1/2004-1/2005+1/2005-1/2006`

    `=1-1/2006=2005/2006`

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