Tính tổng: S=1/2022 – 5/2.4 – 5/4.6 -…- 5/2020.2022 19/08/2021 Bởi Nevaeh Tính tổng: S=1/2022 – 5/2.4 – 5/4.6 -…- 5/2020.2022
`S= 1/2022 – 5/2.4 – 5/4.6 -…-5/2020.2022` `S= 1/2022 – ( 5/2.4 + 5/4.6 +…+5/2020.2022)` Đặt `A= 5/2.4 + 5/4.6 +…+ 5/2020.2022` `A: 5 = 1/2.4 + 1/4.6 +…+1/2020.2022` `A : 5.2 = 2/2.4 + 2/4.6 +…+2/2020.2022` `A: 5.2 = 1/2-1/4 +1/4-1/6 +…+1/2020 – 1/2022` `A:5 .2 = 1/2 – 1/2022` `A = 505/1011` `A = 505/1011 : 2 .5` `A=2525/2022` `=> S= 1/2022 – 2525/2022` `=> S= -1262/1011` Vậy `S= -1262/1011` Bình luận
`S= 1/2022 – 5/2.4 – 5/4.6 -…-5/2020.2022`
`S= 1/2022 – ( 5/2.4 + 5/4.6 +…+5/2020.2022)`
Đặt `A= 5/2.4 + 5/4.6 +…+ 5/2020.2022`
`A: 5 = 1/2.4 + 1/4.6 +…+1/2020.2022`
`A : 5.2 = 2/2.4 + 2/4.6 +…+2/2020.2022`
`A: 5.2 = 1/2-1/4 +1/4-1/6 +…+1/2020 – 1/2022`
`A:5 .2 = 1/2 – 1/2022`
`A = 505/1011`
`A = 505/1011 : 2 .5`
`A=2525/2022`
`=> S= 1/2022 – 2525/2022`
`=> S= -1262/1011`
Vậy `S= -1262/1011`
Xin hay nhất!!!