1/2 – 1/2 . 3 – 1/3 . 4 – 1/4 . 5 – …….-1020/1021

Question

1/2 – 1/2 . 3 – 1/3 . 4 – 1/4 . 5 – …….-1020/1021

in progress 0
Adeline 3 tháng 2021-09-02T15:06:32+00:00 2 Answers 3 views 0

Answers ( )

    0
    2021-09-02T15:07:43+00:00

    Đáp án:

     

    Giải thích các bước giải:

    $\text{Ta có:$\frac{1}{2}-\frac{1}{2.3}-\frac{1}{3.4}-\frac{1}{4.5}-…-\frac{1}{1020.1021}$}$ $\text{$=\frac{1}{2}-(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+…+\frac{1}{1020.1021})$}$

    $\text{$=\frac{1}{2}-(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+…+\frac{1}{1020}-\frac{1}{1021})$}$

    $\text{$=\frac{1}{2}-(\frac{1}{2}-\frac{1}{1021})=\frac{1}{1021}$}$

    0
    2021-09-02T15:07:49+00:00

    Đáp án:

    `1/2 – 1/{2 . 3} – 1/{3 . 4} – 1/{4 . 5} – …….-1/{1020.1021}`

    `=1/2 -(1/{2 . 3} + 1/{3 . 4} + 1/{4 . 5} + …….+1/{1020.1021})`

    `=1/2 -(1/2-1/3+1/3-…+1/1020-1/1021)`

    `=1/2-(1/2-1/1021)`

    `=1/2-1023/2042`

    `=-1/1021`

Leave an answer

Browse

35:5x4+1-9:3 = ? ( )