So sánh: 2018/2019 2019/2020 so sánh ((2018 2019)/(2019 2020)

Lời giải:

\[1 - \frac{{2018}}{{2019}} = \frac{1}{{2019}}\]

\[1 - \frac{{2019}}{{2020}} = \frac{1}{{2020}}\]

Ta có 2019 < 2020, suy ra \[\frac{1}{{2019}} > \frac{1}{{2020}}\]

Suy ra \[ - \frac{1}{{2019}} <  - \frac{1}{{2020}}\]

Suy ra \[1 - \frac{1}{{2019}} < 1 - \frac{1}{{2020}}\]

Vậy \[\frac{{2018}}{{2019}} < \frac{{2019}}{{2020}}\].