Toán Thực hiện phép tính : A = -1-1/3-1/6-1/10-…-1/45 01/12/2021 By Brielle Thực hiện phép tính : A = -1-1/3-1/6-1/10-…-1/45
Đáp án: `A=-1-1/3-1/6-…-1/45` `A=-(1+1/3+1/6+…+1/45)` `1/2A=-(1/2+1/6+1/12+…+1/90)` `1/2A=-(1/(1.2)+1/(2.3)+1/(3.4)+…+1/(9.10))` `1/2A=-(1/1-1/2+1/2-1/3+1/3-1/4+…+1/9-1/10)` `1/2A=-(1/1-1/10)` `1/2A=-9/10` `A=(-9/10)/2=-9/5` Trả lời
`A=-1-1/3-1/6-1/10-…-1/45` `⇒A=-(1+1/3+1/6+…+1/45)` `⇒1/2A=-(1/2+1/6+1/12+…+1/90)` `⇒1/2A=-(1/(1.2)+1/(2.3)+1/(3.4)+…+1/(9.10))` `⇒1/2A=-(1-1/2+1/2-1/3+1/3-1/4+…+1/9-1/10)` `⇒1/2A=-(1-1/10)` `⇒1/2A=-9/10` `⇒A=-9/5` Trả lời
Đáp án:
`A=-1-1/3-1/6-…-1/45`
`A=-(1+1/3+1/6+…+1/45)`
`1/2A=-(1/2+1/6+1/12+…+1/90)`
`1/2A=-(1/(1.2)+1/(2.3)+1/(3.4)+…+1/(9.10))`
`1/2A=-(1/1-1/2+1/2-1/3+1/3-1/4+…+1/9-1/10)`
`1/2A=-(1/1-1/10)`
`1/2A=-9/10`
`A=(-9/10)/2=-9/5`
`A=-1-1/3-1/6-1/10-…-1/45`
`⇒A=-(1+1/3+1/6+…+1/45)`
`⇒1/2A=-(1/2+1/6+1/12+…+1/90)`
`⇒1/2A=-(1/(1.2)+1/(2.3)+1/(3.4)+…+1/(9.10))`
`⇒1/2A=-(1-1/2+1/2-1/3+1/3-1/4+…+1/9-1/10)`
`⇒1/2A=-(1-1/10)`
`⇒1/2A=-9/10`
`⇒A=-9/5`