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10 tháng 10 2022

`[(1/3+1/4) xx 1 1/3 + 2/9 ] : 0,8 - 1/4 + 2021`

`= [(4/12+3/12) xx 4/3 +2/9] :4/5 - 1/4+2021`

`= [7/12 xx 4/3+2/9]:4/5 - 1/4+2021`

`=[7/9+2/9):4/5-1/4+2021`

`=1 :4/5-1/4+2021`

`=1 xx 5/4 -1/4+2021`

`=5/4-1/4+2021`

`=1+2021`

`=2022`

a: =(-1)+(-1)+...+(-1)=-1011

b: =(-5)+(-5)+...+(-5)=-175

18 tháng 10 2021

Bằng 106 nhé nha bn

18 tháng 10 2021
Bằng 106 bạn nha

B/A

\(=\dfrac{1+\dfrac{2020}{2}+1+\dfrac{2019}{3}+...+1+\dfrac{1}{2021}+1}{\dfrac{1}{2}+\dfrac{1}{3}+...+\dfrac{1}{2021}+\dfrac{1}{2022}}\)

\(=\dfrac{2022\left(\dfrac{1}{2}+\dfrac{1}{3}+...+\dfrac{1}{2021}+\dfrac{1}{2022}\right)}{\dfrac{1}{2}+\dfrac{1}{3}+...+\dfrac{1}{2021}+\dfrac{1}{2022}}=2022\)

3 tháng 5 2023

B = \(\dfrac{1}{2002}\) + \(\dfrac{2}{2021}\) + \(\dfrac{3}{2020}\)+...+ \(\dfrac{2021}{2}\) + \(\dfrac{2022}{1}\)

B = \(\dfrac{1}{2002}\) + \(\dfrac{2}{2021}\) + \(\dfrac{3}{2020}\)+...+ \(\dfrac{2021}{2}\) + 2022

B = 1 + ( 1 + \(\dfrac{1}{2022}\)) + ( 1 + \(\dfrac{2}{2021}\)) + \(\left(1+\dfrac{3}{2020}\right)\)+ ... + \(\left(1+\dfrac{2021}{2}\right)\) 

B = \(\dfrac{2023}{2023}\) + \(\dfrac{2023}{2022}\) + \(\dfrac{2023}{2021}\) + \(\dfrac{2023}{2020}\) + ...+ \(\dfrac{2023}{2}\) 

B = 2023 \(\times\) ( \(\dfrac{1}{2023}\) + \(\dfrac{1}{2022}\) + \(\dfrac{1}{2021}\) + \(\dfrac{1}{2020}\)+ ... + \(\dfrac{1}{2}\))

Vậy B > C 

 

23 tháng 3 2020

\(0,8.\sqrt{\frac{25}{9}}-\frac{2}{7}.\sqrt{5}.\frac{4}{9}+\left(-\frac{1}{2}\right)^3.4^2\)

\(=\frac{4}{3}-0,29+\left(-2\right)\)

\(=\frac{313}{300}+\left(-2\right)\)

\(=-\frac{287}{300}\)

P/s : kh chắc nhé

\(0,8.\sqrt{\frac{25}{9}}-\frac{2}{7}.\sqrt{5}.\frac{4}{9}+\left(\frac{-1}{2}\right)^3.4^2\)

\(=0,8.\frac{5}{3}-\frac{2}{7}.\frac{11}{2}.\frac{4}{9}+\frac{-1}{8}\)

\(=\frac{4}{3}-\frac{44}{63}+\frac{-1}{8}\)

\(=\frac{-1}{8}\)

18 tháng 10 2021

Xin lỗi m.n nhé gửi nhầm tí

16 tháng 7 2023

a) Ta có:

2A=2.(12+122+123+...+122020+122021)2�=2.12+122+123+...+122  020+122  021

2A=1+12+122+123+...+122019+1220202�=1+12+122+123+...+122  019+122  020

Suy ra: 2A−A=(1+12+122+123+...+122019+122020)2�−�=1+12+122+123+...+122  019+122  020

                             −(12+122+123+...+122020+122021)−12+122+123+...+122  020+122  021

Do đó A=1−122021<1�=1−122021<1.

Lại có B=13+14+15+1360=20+15+12+1360=6060=1�=13+14+15+1360=20+15+12+1360=6060=1.

Vậy A < B.