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9 tháng 10 2018

\(C=\left(2018^{2019}+2018^{2018}+...+2018^2+2018\right)2017+1\)

\(=\left(2018^{2019}+2018^{2018}+...+2018^2+2018\right)2018-\left(2018^{2019}+2018^{2018}+...+2018\right)-1\)

\(=\left(2018^{2020}+2018^{2019}+...+2018^3+2018^2\right)-\left(2018^{2019}+2018^{2018}+...+2018^2+2018\right)+1\)\(=2018^{2020}-2018+1\)

\(=2018^{2020}-2017\)

15 tháng 10 2018

\(M=\left(2018^{2019}+2018^{2018}+...+2018^2+2018\right)2017+1\)

Gọi \(A=2018^{2019}+2018^{2018}+...+2018^2+2018\)

\(\Rightarrow2018A=2018^{2020}+2018^{2019}+...+2018^3+2018^2\)

\(\Rightarrow2018A-A=2018^{2020}-2018\)

\(\Rightarrow2017A=2018^{2020}-2018\)

\(\Rightarrow A=\left(2018^{2020}-2018\right)\div2017\)

\(\Rightarrow M=\left(2018^{2020}-2018\right)\div2017.2017+1\)

\(\Rightarrow M=2018^{2020}-2018+1\)

\(\Rightarrow M=2018^{2020}-2017\)

11 tháng 9 2018

Dễ thế MJ!!11

2 tháng 7 2018

Đặt \(A=\frac{2^{2017}+1}{2^{2018}+1}\Rightarrow2A=\frac{2^{2018}+2}{2^{2018}+1}=\frac{2^{2018}+1+1}{2^{2018}+1}=1+\frac{1}{2^{2018}+1}\)

\(B=\frac{2^{2018}+1}{2^{2019}+1}\Rightarrow2B=\frac{2^{2019}+2}{2^{2019}+1}=\frac{2^{2019}+1+1}{2^{2019}+1}=1+\frac{1}{2^{2019}+1}\)

Vì \(2^{2019}+1>2^{2018}+1\Rightarrow\frac{1}{2^{2019}+1}< \frac{1}{2^{2018}+1}\)

\(\Rightarrow2A>2B\Rightarrow A>B\)

30 tháng 1 2018

Do x=2017 nên x+1=2018

Với x+1=2018 thì y trở thành

y= x5-(x+1).x4+(x+1).x3-(x+1).x2+(x+1).x-1

= x5- x5-x4+x4+x3-x3-x2+x-1=x-1

Với x=2017, giá trị biểu thức f(x) là

f(2017)=2017-1=2016

Vậy ...

31 tháng 7 2018

\(3A=1+\frac{1}{3}+...+\frac{1}{3^{2017}}\)

\(3A-A=\left(1+\frac{1}{3}+...+\frac{1}{3^{2017}}\right)-\left(\frac{1}{3}+\frac{1}{3^2}+...+\frac{1}{3^{2018}}\right)\)

\(2A=1-\frac{1}{3^{2018}}\)

\(A=\frac{1-\frac{1}{3^{2018}}}{2}\)

31 tháng 7 2018

đặt \(A=\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+...+\frac{1}{3^{2018}}\)

\(3A=1+\frac{1}{3}+\frac{1}{3^2}+...+\frac{1}{3^{2017}}\)

\(3A-A=\left(1+\frac{1}{3}+\frac{1}{3^2}+...+\frac{1}{3^{2017}}\right)-\left(\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+...+\frac{1}{3^{2018}}\right)\)

\(2A=1-\frac{1}{3^{2018}}\)

\(A=\frac{1-\frac{1}{3^{2018}}}{2}\)

đặt \(B=1+5+5^2+...+5^{2018}\)

\(5B=5+5^2+5^3+...+5^{2019}\)

\(5B-B=\left(5+5^2+5^3+...+5^{2019}\right)-\left(1+5+5^2+...+5^{2018}\right)\)

\(4B=5^{2019}-1\)

\(B=\frac{5^{2019}-1}{4}\)

14 tháng 10 2018

A=22019-(22018+22017+...+21+20)

Đặt M =22018+22017+...+21+20

M=22018+22017+...+2+1

2M=22019+22018+...+22+2

2M-M=(22019+22018+...+22+2)-(22018+22017+...+2+1)

M=22019-1

Suy ra:A=22019-(22019-1)

A=22019-22019+1

A=1

Vậy A=1

14 tháng 10 2018

Ta có : \(A=2^{2019}-\left(2^{2018}+2^{2017}+...+2^1+2^0\right)\)

Đặt \(B=2^0+2^1+...+2^{2017}+2^{2018}\\ \Rightarrow2B=2+2^2+...+2^{2019}\\ \Rightarrow2B-B=\left(2+2^2+...+2^{2019}\right)-\left(2^0+2^1+...+2^{2017}+2^{2018}\right)\\ \Rightarrow B=2^{2019}-2^0\\ \Rightarrow A=2^{2019}-\left(2^{2019}-2^0\right)\\ \Rightarrow A=2^0=1\)

Vậy A=1