Toán Tính: E= 4/40 + 4/88 + 4/54 + … + 4/4828 21/07/2021 By Nevaeh Tính: E= 4/40 + 4/88 + 4/54 + … + 4/4828
`E = 4/40 + 4/88 + 4/154 + … + 4/4828` `= 4/(5 . 8) + 4/(8 . 11) + 4/(11 . 14) + … + 4/(68 . 71)` `=> E/4 = 1/(5 . 8) + 1/(8 . 11) + 1/(11 . 14) + … + 1/(68 . 71)` `=> 3/4E = 3/(5 . 8) + 3/(8 . 11) + 3/(11 . 14) + … + 3/(68 . 71)` `= 1/5 – 1/8 + 1/8 – 1/11 + 1/11 – 1/14 + … + 1/68 – 1/71` `= 1/5 – 1/71 = 71/355 – 5/355 = 66/355` `=> E = 66/355 ÷ 3/4 = 88/355` Vậy `E = 88/355`. Trả lời
Đáp án: Giải thích các bước giải: E=`4/40+4/88+4/54+ … +4/4828` E=4/5×8+4/8×11+. . .+4/68 x71 E= `4/3` x ( 3/5×8+3/8×11+. . .+3/68×71) E=`4/3` x ( `1/5`-`1/8`+`1/8`-`1/11`+. . .+`1/68`-`1/71`) E=`4/3` x ( `1/5` – `1/71`) E=`4/3` x` 66/355` E=`88/355` Trả lời
`E = 4/40 + 4/88 + 4/154 + … + 4/4828`
`= 4/(5 . 8) + 4/(8 . 11) + 4/(11 . 14) + … + 4/(68 . 71)`
`=> E/4 = 1/(5 . 8) + 1/(8 . 11) + 1/(11 . 14) + … + 1/(68 . 71)`
`=> 3/4E = 3/(5 . 8) + 3/(8 . 11) + 3/(11 . 14) + … + 3/(68 . 71)`
`= 1/5 – 1/8 + 1/8 – 1/11 + 1/11 – 1/14 + … + 1/68 – 1/71`
`= 1/5 – 1/71 = 71/355 – 5/355 = 66/355`
`=> E = 66/355 ÷ 3/4 = 88/355`
Vậy `E = 88/355`.
Đáp án:
Giải thích các bước giải:
E=`4/40+4/88+4/54+ … +4/4828`
E=4/5×8+4/8×11+. . .+4/68 x71
E= `4/3` x ( 3/5×8+3/8×11+. . .+3/68×71)
E=`4/3` x ( `1/5`-`1/8`+`1/8`-`1/11`+. . .+`1/68`-`1/71`)
E=`4/3` x ( `1/5` – `1/71`)
E=`4/3` x` 66/355`
E=`88/355`