Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(3A=3^2+3^3+3^4+...+3^{2021}\)
\(2A=3A-A=3^{2021}-3\)
\(\Rightarrow2A+3=3^{2021}-3+3=3^{2021}=3^n\Rightarrow n=2021\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có: 3A=32+33+...+3101
3A-A=2A=(32+33+...+3101)-(3+32+...+3100)
2A=3101-3
A=\(\frac{3^{101}-3}{2}\)
=>2A+3=2.\(\frac{3^{101}-3}{2}\)+3
=(3101-3)+3
=3101
Mà 2A+3=3n
=>3101=3n
=>n=101
A=3+32+33+...+3100
2A=(3+32+33+...+3100)x2
2A=32+33+34...+3101
2A-A=3101-3
mà 3n=2A+3=3101-3+3=3101
suy ra n=101
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có \(A=3+3^2+3^3+...+3^{100}\)
\(\Rightarrow3A=3^2+3^3+3^4+...+3^{101}\)
\(\Rightarrow3A-A=3^{101}-3\)
\(2A=3^{101}-3\)
Ta có \(2A+3=3^n\)
hay \(3^{101}-3+3=3^n\)
\(3^{101}=3^n\)
\(n=101\)
A=3+32+33+.....+3100
3a=3.(3+32+33+....+3100)
3A=32+33+34+....+3101
3A-A=(32+33+34+....+3101)-(3+32+33+.....+3100)
2A=3101-3
2A+3=3101-3+3
2A+3=3101
3n=3101
=>n\(\in\)(101)
Chúc bn học tốt
![](https://rs.olm.vn/images/avt/0.png?1311)
\(A=1+3+3^2+...+3^{2016}+3^{2017}\)
\(3A=3+3^2+3^3+...+3^{2017}+3^{2018}\)
\(3A-A=3^{2018}-1\)
\(2A+1=3^{2018}\)
Vậy n = 2018
3A=3+3^2+3^3+...+3^2018
-A=1+3+3^2+...+3^2017
2A=3^2018-1
khi đó ta có 2A+1=3^2018-1+1=3^2018=3^n
=>n=2018
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
A=\(3+3^2+3^3+...+3^{100}\)
3A=\(3^2+3^3+3^4+...+3^{101}\)
3A - A=\(3^2+3^3+3^4+...+3^{101}-3-3^2-3^3-...-3^{100}\)
2A = \(3^{101}-3\)
=>\(2A+3=3^n\)
=>\(3^{101}-3+3=3^n\)
=>3\(^{101}=3^n\)
=>n=101
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
A=3+3^2+3^3+...+3^100
=>3A=3^2+3^3+3^4+...+3^101
=>3A-A=2A=3^101-3
mà 2A+3=3^n
=>3^101-3+3=3^n
=>3^n=3^101
=>n=101
A = 3 + 32 + 33 + ...+3100
3A = 32 + 33 + 34 + ...+ 3101
3A - A = ( 32 + 33 + 34 + ...+ 3101 ) - ( 3 + 32 + 33 + ...+3100 )
2A = 3101 - 3
Thay vào 2A + 3 = 3n ta có
3101 - 3 + 3 = 3n
3101 = 3n
=> n = 101
A = 3 + 32 + 33 +....+ 3100
\(\Rightarrow\) 3A= 3.(3 + 32 + 33 +....+ 3100)
\(\Rightarrow\) 3A= 32 + 33 + 34 +.....+ 3101
\(\Rightarrow\)3A - A= (32 + 33 + 34 +.....+ 3101) - (3 + 32 + 33 +....+ 3100)
\(\Rightarrow\)2A= 3101 - 3
mà 2A + 3 = 3n
\(\Rightarrow\)3101 - 3 + 3 = 3n
\(\Rightarrow\)3101 = 3n
\(\Rightarrow\)n=101