2022/1.2+2022/2.3+2022/3.4+.......+2022/2021.2022 mik đang cần gấp

2 câu trả lời

Answer

`2022/{1 . 2} + 2022/{2 . 3} + 2022/{3 . 4} + ... + 2022/{2021 . 2022}`

`= 1/1 . (2022/{1 . 2} + 2022/{2 . 3} + 2022/{3 . 4} + ... + 2022/{2021 . 2022})`

`= 2022/1 . (1/{1 . 2} + 1/{2 . 3} + 1/{3 . 4} + ... + 1/{2021 . 2022})`

`= 2022 . (1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + ... + 1/2021 - 1/2022)`

`= 2022 . (1 - 1/2022)`

`= 2022 . 2021/2022`

`= 2021` 

Đáp án:

 

Giải thích các bước giải:

`S = 2022/1.2 + 2022/2.3 + 2022/3.4 + ... + 2022/2021.2022`

`S/2022 = 1/1.2 + 1/2.3 + 1/3.4 + ... + 1/2021.2022`

`S/2022 = 1/1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + ... + 1/2021 - 1/2022`

`S/2022 = 1 - 1/2022`

`S/2022 = 2021/2022`

`S = 2021`