Toán Tính `A=4/21+4/77+4/165+4/285+4/437+4/621`. 16/07/2021 By Nevaeh Tính `A=4/21+4/77+4/165+4/285+4/437+4/621`.
`A = 4/21 + 4/77 + 4/165 + 4/285 + 4/437 + 4/621` `= 4/(3.7) + 4/(7.11) + 4/(11.15) + 4/(15.19) + 4/(19.23) + 4/(23.27)` `= 1/3 – 1/7 + 1/7 – 1/11 + 1/11 – 1/15 + 1/15 – 1/19 + 1/19 – 1/23 + 1/23 – 1/27` `= 1/3 – 1/27` `= 9/27-1/27` `= 8/27` Vậy `A = 8/27` Trả lời
Đáp án: Giải thích các bước giải: A=`4/21`+`4/77`+`4/165`+`4/285`+`4/437`+`4/621` A=`4/3.7`+`4/7.11`+`4/11.15`+`4/15.19`+`4/19.23`+`4/23.27` A=`1/3`-`1/7`+`1/7`-`1/11`+`1/11`-`1/15`+`1/15`-`1/19`+`1/19`-`1/23`+`1/23`-`1/27` A=`1/3`-`1/27` A=`8/27` Trả lời
`A = 4/21 + 4/77 + 4/165 + 4/285 + 4/437 + 4/621`
`= 4/(3.7) + 4/(7.11) + 4/(11.15) + 4/(15.19) + 4/(19.23) + 4/(23.27)`
`= 1/3 – 1/7 + 1/7 – 1/11 + 1/11 – 1/15 + 1/15 – 1/19 + 1/19 – 1/23 + 1/23 – 1/27`
`= 1/3 – 1/27`
`= 9/27-1/27`
`= 8/27`
Vậy `A = 8/27`
Đáp án:
Giải thích các bước giải:
A=`4/21`+`4/77`+`4/165`+`4/285`+`4/437`+`4/621`
A=`4/3.7`+`4/7.11`+`4/11.15`+`4/15.19`+`4/19.23`+`4/23.27`
A=`1/3`-`1/7`+`1/7`-`1/11`+`1/11`-`1/15`+`1/15`-`1/19`+`1/19`-`1/23`+`1/23`-`1/27`
A=`1/3`-`1/27`
A=`8/27`