Toán Tính nhanh tổng số sau: M = 1/4+1/10+1/18+1/28+1/40+1/54+1/70 30/07/2021 By Lydia Tính nhanh tổng số sau: M = 1/4+1/10+1/18+1/28+1/40+1/54+1/70
Giải thích các bước giải: `M=1/4+1/10+1/18+1/28+1/40+1/54+1/70` `=> M = (1/4+1/28) + (1/10+1/70) + (1/18+1/54) + 1/40` `=> M = (7/28+1/28) + (7/70 + 1/70) + (3/54 + 1/54) + 1/40` `=> M = 8/28 + 8/70 + 4/54 + 1/40` `=> M = 2/7 + 4/35 + 2/27 + 1/40` `=> M = 2/5 + 2/27 + 1/40` `=> M = (16/40 + 1/40) + 2/27` `=> M = 17/40 + 2/27` `=> M = 539/1080` Trả lời
Đáp án: Tham khảo ạ≈ω Giải thích các bước giải: `M = 1/4 + 1/10 + 1/18 + 1/28 + 1/40 + 1/54 + 1/70 ` `M = 1/(2xx2) + 1/(2xx5) + 1/(2xx9) + 1/(2xx14) + 1/(2xx20) + 1/(2xx27) + 1/(2xx35)` `M = 1/2 xx ( 1/2 + 1/5 + 1/9 + 1/14 + 1/20 + 1/27 + 1/35)` `M = 1/2 xx [(1/2 + 1/5 + 1/20) + (1/9 + 1/27) + (1/14 + 1/35)]` `M = 1/2xx (3/4 + 4/27 + 1/10)` `M = 1/2xx 539/540` `M = 539/1080` Trả lời
Giải thích các bước giải:
`M=1/4+1/10+1/18+1/28+1/40+1/54+1/70`
`=> M = (1/4+1/28) + (1/10+1/70) + (1/18+1/54) + 1/40`
`=> M = (7/28+1/28) + (7/70 + 1/70) + (3/54 + 1/54) + 1/40`
`=> M = 8/28 + 8/70 + 4/54 + 1/40`
`=> M = 2/7 + 4/35 + 2/27 + 1/40`
`=> M = 2/5 + 2/27 + 1/40`
`=> M = (16/40 + 1/40) + 2/27`
`=> M = 17/40 + 2/27`
`=> M = 539/1080`
Đáp án:
Tham khảo ạ≈ω
Giải thích các bước giải:
`M = 1/4 + 1/10 + 1/18 + 1/28 + 1/40 + 1/54 + 1/70 `
`M = 1/(2xx2) + 1/(2xx5) + 1/(2xx9) + 1/(2xx14) + 1/(2xx20) + 1/(2xx27) + 1/(2xx35)`
`M = 1/2 xx ( 1/2 + 1/5 + 1/9 + 1/14 + 1/20 + 1/27 + 1/35)`
`M = 1/2 xx [(1/2 + 1/5 + 1/20) + (1/9 + 1/27) + (1/14 + 1/35)]`
`M = 1/2xx (3/4 + 4/27 + 1/10)`
`M = 1/2xx 539/540`
`M = 539/1080`