4/2.4+4/4.6+4/6.8+……..+4/2018.2020 Giúp.mình vs ạ mai mình ktra ạ 29/08/2021 Bởi Alexandra 4/2.4+4/4.6+4/6.8+……..+4/2018.2020 Giúp.mình vs ạ mai mình ktra ạ
Đáp án + Giải thích các bước giải: `4/(2.4) + 4/(4.6) + … + 4/(2018.2020)` `= 2 . ( 2/(2.4) + 2/(4.6) + … + 2/(2018.2020))` `= 2 . ( 1/2 – 1/4 + 1/4 – 1/6 + … + 1/2018 – 1/2020 )` `= 2 . ( 1/2 – 1/2020 ) = 2 . 1009/2020 = 1009/1010` Bình luận
`=2(2/(2*4)+2/(4*6)+…+2/(2018*2020))` `=2(1/2-1/4+1/4-1/6+…+1/2018-1/2020)` `=2(1/2-1/2020)` `=2(1009/2020)` `=1009/1010` Bình luận
Đáp án + Giải thích các bước giải:
`4/(2.4) + 4/(4.6) + … + 4/(2018.2020)`
`= 2 . ( 2/(2.4) + 2/(4.6) + … + 2/(2018.2020))`
`= 2 . ( 1/2 – 1/4 + 1/4 – 1/6 + … + 1/2018 – 1/2020 )`
`= 2 . ( 1/2 – 1/2020 ) = 2 . 1009/2020 = 1009/1010`
`=2(2/(2*4)+2/(4*6)+…+2/(2018*2020))`
`=2(1/2-1/4+1/4-1/6+…+1/2018-1/2020)`
`=2(1/2-1/2020)`
`=2(1009/2020)`
`=1009/1010`