Toán Tính S=1/3+1/9+1/18+1/39+1/45+1/63+…+1/14850 10/11/2021 By Genesis Tính S=1/3+1/9+1/18+1/39+1/45+1/63+…+1/14850
Đáp án: Giải thích các bước giải: `S=1/3+1/9+1/18+1/39+1/45+1/63+…+1/14850` `S=1/1.3+1/3.3+1/3.6+1/3.15+1/3.21+…+1/3.4950` `S/3=1+1/3+1/6+1/15+1/21+…+1/4950` `S/6=1/2+1/6+1/12+1/30+1/42+…+1/9900` `S/6=(1/1.2+1/2.3+1/3.4+1/4.5+1/5.6+1/6.7+…+1/99.100)-1/4.5` `S/6=(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+…+1/99-1/100)-1/4-1/5` `S/6=(1-1/100)-1/4-1/5` `S/6=99/100-(1/4+1/5)` `S/6=99/100-9/20` `S/6=27/50` `S=27/50*6` `S=81/25` Trả lời
Đáp án:
Giải thích các bước giải:
`S=1/3+1/9+1/18+1/39+1/45+1/63+…+1/14850`
`S=1/1.3+1/3.3+1/3.6+1/3.15+1/3.21+…+1/3.4950`
`S/3=1+1/3+1/6+1/15+1/21+…+1/4950`
`S/6=1/2+1/6+1/12+1/30+1/42+…+1/9900`
`S/6=(1/1.2+1/2.3+1/3.4+1/4.5+1/5.6+1/6.7+…+1/99.100)-1/4.5`
`S/6=(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+…+1/99-1/100)-1/4-1/5`
`S/6=(1-1/100)-1/4-1/5` `S/6=99/100-(1/4+1/5)`
`S/6=99/100-9/20`
`S/6=27/50`
`S=27/50*6`
`S=81/25`