Toán A. 1 / 1 x 2 + 1 / 2 x 3 + 1 / 3 x 4 + …. + 1 / 2019 x 2020 08/09/2021 By Bella A. 1 / 1 x 2 + 1 / 2 x 3 + 1 / 3 x 4 + …. + 1 / 2019 x 2020
$\dfrac{1}{1 × 2}$ + $\dfrac{1}{2 × 3}$ + …. + $\dfrac{1}{2019 × 2020}$ $\text{= 1 – $\dfrac{1}{2}$ + $\dfrac{1}{2}$ – $\dfrac{1}{2}$ + … – $\dfrac{1}{2020}$}$ $\text{= 1 – $\dfrac{1}{2020}$}$ $\text{= $\dfrac{2019}{2020}$}$ Trả lời
A=$\frac{1}{1×2}$+$\frac{1}{2×3}$+$\frac{1}{3×4}$+…..+$\frac{1}{2019×2020}$ A=1-$\frac{1}{2}$+$\frac{1}{2}$-$\frac{1}{3}$+$\frac{1}{3}$-$\frac{1}{4}$+……+$\frac{1}{2019}$- $\frac{1}{2020}$ A=1-$\frac{1}{2020}$=$\frac{2019}{2020}$ Chúc bn học totoa<3 Trả lời
$\dfrac{1}{1 × 2}$ + $\dfrac{1}{2 × 3}$ + …. + $\dfrac{1}{2019 × 2020}$
$\text{= 1 – $\dfrac{1}{2}$ + $\dfrac{1}{2}$ – $\dfrac{1}{2}$ + … – $\dfrac{1}{2020}$}$
$\text{= 1 – $\dfrac{1}{2020}$}$
$\text{= $\dfrac{2019}{2020}$}$
A=$\frac{1}{1×2}$+$\frac{1}{2×3}$+$\frac{1}{3×4}$+…..+$\frac{1}{2019×2020}$
A=1-$\frac{1}{2}$+$\frac{1}{2}$-$\frac{1}{3}$+$\frac{1}{3}$-$\frac{1}{4}$+……+$\frac{1}{2019}$- $\frac{1}{2020}$
A=1-$\frac{1}{2020}$=$\frac{2019}{2020}$
Chúc bn học totoa<3