so sánh 2 phân số 2021/2022 và 2021/2020
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\(\dfrac{-11}{-32}>\dfrac{16}{49}\)
\(\dfrac{-2020}{-2021}>\dfrac{-2021}{2022}\)
1) \(16^{2020}+\dfrac{1}{16^{2021}}+1\)
\(=16^{2021}\div16^{2020}+1\)
\(=16+1\)
\(=17\)
2) \(16^{2021}+\dfrac{1}{16^{2022}}+1\)
\(=16^{2022}\div16^{2021}+1\)
\(=16+1\)
= 17
Vì 17=17 nên \(16^{2020}+\dfrac{1}{16^{2021}}+1=16^{2021}+\dfrac{1}{16^{2022}}+1\)
a: Đặt \(A=\sqrt{2021}-\sqrt{2020}\) và \(B=\sqrt{2022}-\sqrt{2021}\)
\(A=\sqrt{2021}-\sqrt{2020}=\frac{2021-2020}{\sqrt{2021}+\sqrt{2020}}=\frac{1}{\sqrt{2021}+\sqrt{2020}}\)
\(B=\sqrt{2022}-\sqrt{2021}=\frac{2022-2021}{\sqrt{2022}+\sqrt{2021}}=\frac{1}{\sqrt{2022}+\sqrt{2021}}\)
Ta có: \(\sqrt{2021}+\sqrt{2020}<\sqrt{2022}+\sqrt{2021}\)
=>\(\frac{1}{\sqrt{2021}+\sqrt{2020}}>\frac{1}{\sqrt{2022}+\sqrt{2021}}\)
=>A>B
b: Đặt \(A=\sqrt{2022}-\sqrt{2020}\) và \(B=\sqrt{2020}-\sqrt{2018}\)
\(A=\sqrt{2022}-\sqrt{2020}=\frac{2022-2020}{\sqrt{2022}+\sqrt{2020}}=\frac{2}{\sqrt{2022}+\sqrt{2020}}\)
\(B=\sqrt{2020}-\sqrt{2018}=\frac{2020-2018}{\sqrt{2020}+\sqrt{2018}}=\frac{2}{\sqrt{2020}+\sqrt{2018}}\)
TA có: \(\sqrt{2022}+\sqrt{2020}>\sqrt{2020}+\sqrt{2018}\)
=>\(\frac{2}{\sqrt{2022}+\sqrt{2020}}<\frac{2}{\sqrt{2020}+\sqrt{2018}}\)
=>A<B
Lời giải:
$6A=\frac{6^{2021}+6}{6^{2021}+1}=1+\frac{5}{6^{2021}+1}>1+\frac{5}{6^{2022}+1}$
$=\frac{6^{2022}+6}{6^{2022}+1}=6.\frac{6^{2021}+1}{6^{2022}+1}=6B$
$\Rightarrow A>B$
Có: \(2022>2020\)
\(\Rightarrow\dfrac{1}{2022}< \dfrac{1}{2020}\)
\(\Rightarrow\dfrac{2021}{2022}< \dfrac{2021}{2020}\)