Toán Tính tổng S=1/1.2+1/2.3+1/3.4+………….1/98.99+1/99.100 12/10/2021 By Delilah Tính tổng S=1/1.2+1/2.3+1/3.4+………….1/98.99+1/99.100
$S=1/1.2+1/2.3+1/3.4+………….+1/98.99+1/99.100$ $⇔S = 1 – 1/2 + 1/2 – 1/3 + 1/3 – 1/4 + …. +1/98 – 1/99 + 1/99 – 1/100$ $⇔S = 1 – 1/100$ $⇔S= 99/100$ Trả lời
Áp dụng :`1/[n(n+1)]=1/n – 1/(n+1)` `S=1/(1.2)+1/(2.3)+…+1/(99.100)` `S=1-1/2+1/2-1/3+…+1/99-1/100` `S=1-1/100` `S=99/100` Trả lời
$S=1/1.2+1/2.3+1/3.4+………….+1/98.99+1/99.100$
$⇔S = 1 – 1/2 + 1/2 – 1/3 + 1/3 – 1/4 + …. +1/98 – 1/99 + 1/99 – 1/100$
$⇔S = 1 – 1/100$
$⇔S= 99/100$
Áp dụng :`1/[n(n+1)]=1/n – 1/(n+1)`
`S=1/(1.2)+1/(2.3)+…+1/(99.100)`
`S=1-1/2+1/2-1/3+…+1/99-1/100`
`S=1-1/100`
`S=99/100`