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22 tháng 2

Ta có:
\(\dfrac{2022}{2021}=\dfrac{2021+1}{2021}=1+\dfrac{1}{2021}\)

\(\dfrac{2021}{2020}=\dfrac{2020+1}{2020}=1+\dfrac{1}{2020}\)

Mà: \(2021>2020\)

\(\Rightarrow\dfrac{1}{2021}< \dfrac{1}{2020}\)

\(\Rightarrow1+\dfrac{1}{2021}< 1+\dfrac{1}{2020}\)

\(\Rightarrow\dfrac{2022}{2021}< \dfrac{2021}{2020}\)

22 tháng 2

\(\dfrac{2022}{2021}=1+\dfrac{1}{2021}\)

\(\dfrac{2021}{2020}=1+\dfrac{1}{2020}\)

Do \(2021>2020\Rightarrow\dfrac{1}{2021}< \dfrac{1}{2020}\)

\(\Rightarrow1+\dfrac{1}{2021}< 1+\dfrac{1}{2020}\)

Vậy \(\dfrac{2022}{2021}< \dfrac{2021}{2020}\)

\(2.A=\frac{2^{2021}-2}{2^{2021}-1}=1-\frac{1}{2^{2021}-1}\)

\(2B=\frac{2^{2022}-2}{2^{2022}-1}=1-\frac{1}{2^{2022}-1}\)

dó \(\frac{1}{2^{2022}-1}< \frac{1}{2^{2021}-1}\Rightarrow1-\frac{1}{2^{2022}-1}>1-\frac{1}{2^{2021}-1}\Rightarrow A< B\)

HT

14 tháng 2 2022

\(\dfrac{-11}{-32}>\dfrac{16}{49}\)

\(\dfrac{-2020}{-2021}>\dfrac{-2021}{2022}\)

14 tháng 2 2022

giải thích giúp mik dc ko ạ 

 

AH
Akai Haruma
Giáo viên
30 tháng 4 2023

Lời giải:
$10A=\frac{10^{2021}-10}{10^{2021}-1}=\frac{10^{2021}-1-9}{10^{2021}-1}$

$=1-\frac{9}{10^{2021}-1}>1$

$10B=\frac{10^{2022}+10}{10^{2022}+1}=\frac{10^{2022}+1+9}{10^{2022}+1}$

$=1+\frac{9}{10^{2022}+1}<1$

$\Rightarrow 10A> 1> 10B$

Suy ra $A> B$

16 tháng 5 2022

Ta có:

\(10A=\dfrac{10\left(10^{2020}+1\right)}{10^{2021}+1}=\dfrac{10^{2021}+10}{10^{2021}+1}=1+\dfrac{9}{10^{2021}+1}\)

\(10B=\dfrac{10\left(10^{2021}+1\right)}{10^{2022}+1}=\dfrac{10^{2022}+10}{10^{2022}+1}=1+\dfrac{9}{10^{2022}+1}\)

⇒ \(10A>10B\) ( vì \(\dfrac{9}{10^{2021}+1}>\dfrac{9}{10^{2022}+1}\) )

Suy ra:  \(A>B\)

AH
Akai Haruma
Giáo viên
29 tháng 4 2022

Lời giải:

$6A=\frac{6^{2021}+6}{6^{2021}+1}=1+\frac{5}{6^{2021}+1}>1+\frac{5}{6^{2022}+1}$
$=\frac{6^{2022}+6}{6^{2022}+1}=6.\frac{6^{2021}+1}{6^{2022}+1}=6B$

$\Rightarrow A>B$

Giải:

Ta có: N=2019+2020/2020+2021

=>N=2019/2020+2021 + 2020/2020+2021

Vì 2019/2020 > 2019/2020+2021 ; 2020/2021 > 2020/2020+2021

=>M>N

Vậy ...

Chúc bạn học tốt!

Ta có : \(\dfrac{2019}{2020}>\dfrac{2019}{2020+2021}\)

            \(\dfrac{2020}{2021}>\dfrac{2020}{2020+2021}\)

\(\Rightarrow\dfrac{2019}{2020}+\dfrac{2020}{2021}>\dfrac{2019+2020}{2020+2021}\)

\(\Rightarrow M>N\)

Tham khảo:

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1 tháng 5 2023

Áp dụng tính chất : Nếu \(\dfrac{a}{b}\) < 1 thì \(\dfrac{a}{b}\) < \(\dfrac{a+n}{b+n}\) ( a ϵ N; b; n ϵ N* )

Ta có \(B=\dfrac{10^{2021}+1}{10^{2022}+1}< \dfrac{10^{2021}+10}{10^{2022}+10}=\dfrac{10\left(10^{2020}+1\right)}{10\left(10^{2021}+1\right)}=\dfrac{10^{2020}+1}{10^{2021}+1}=A\)

Vậy A > B

1 tháng 5 2023

A = \(\dfrac{10^{2020}+1}{10^{2021}+1}\) ⇒ 10\(\times\) A = \(\dfrac{10^{2020}+1}{10^{2021}+1}\) \(\times\) 10

10A = \(\dfrac{10^{2021}+10}{10^{2021}+1}\) =1+\(\dfrac{9}{10^{2021}+1}\)

B = \(\dfrac{10^{2021}+1}{10^{2022}+1}\) ⇒ 10 \(\times\) B = \(\dfrac{10^{2021}+1}{10^{2022}+1}\) \(\times\) 10 

10B = \(\dfrac{10^{2022}+10}{10^{2022}+1}\) = 1 + \(\dfrac{9}{10^{2022}+1}\)

Vì \(\dfrac{9}{10^{2021}+1}\) > \(\dfrac{9}{10^{2022}+1}\)

Vậy 10A > 10B ⇒ A > B 

7 tháng 5 2023

Ta có:2019>4
=>2019/2020+2020/2021+2021/2022+2019>4
=>a>4(dpcm)