1+1/2+1/2^2+1/2^3+…..+1/2^2012 giải hộ nha 16/08/2021 Bởi Remi 1+1/2+1/2^2+1/2^3+…..+1/2^2012 giải hộ nha
đặt` :A=1+1/2+1/2^2+1/2^3+…..+1/2^2012``⇔2A=2+1+1/2+1/2^2+1/2^3+…..+1/2^2011` `⇔A=2-1/2^2012` Bình luận
Đáp án: `text{Đặt A =}` `1 + 1/2 + 1/2^2 + 1/2^3 + … + 1/2^{2012}` `⇔ 2A = 1 + 2 + 1/2 + 1/2^2 + …. + 1/2^{2011}` `⇔ 2A – A = (1 + 2 + 1/2 + 1/2^2 + …. + 1/2^{2011}) – (1 + 1/2 + 1/2^2 + 1/2^3 + … + 1/2^{2012})` `⇔ A = 2 – 1/2^{2012}` `text{Vậy A=}` `2 – 1/2^{2012}` Bình luận
đặt` :A=1+1/2+1/2^2+1/2^3+…..+1/2^2012`
`⇔2A=2+1+1/2+1/2^2+1/2^3+…..+1/2^2011`
`⇔A=2-1/2^2012`
Đáp án:
`text{Đặt A =}` `1 + 1/2 + 1/2^2 + 1/2^3 + … + 1/2^{2012}`
`⇔ 2A = 1 + 2 + 1/2 + 1/2^2 + …. + 1/2^{2011}`
`⇔ 2A – A = (1 + 2 + 1/2 + 1/2^2 + …. + 1/2^{2011}) – (1 + 1/2 + 1/2^2 + 1/2^3 + … + 1/2^{2012})`
`⇔ A = 2 – 1/2^{2012}`
`text{Vậy A=}` `2 – 1/2^{2012}`