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15 tháng 9 2019

\(A=\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(\Leftrightarrow2A=\left(3-1\right)\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(\Leftrightarrow2A=\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(\Leftrightarrow2A=\left(3^4-1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(\Leftrightarrow2A=\left(3^8-1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(\Leftrightarrow2A=\left(3^{16}-1\right)\left(3^{16}+1\right)\)

\(\Leftrightarrow2A=3^{32}-1\)

\(\Leftrightarrow A=3^{31}-\frac{1}{2}\)

12 tháng 9 2021

\(\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)=\dfrac{1}{2}\left(3-1\right)\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)=\dfrac{1}{2}.\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)=\dfrac{1}{2}\left(3^{32}-1\right)=\dfrac{3^{32}}{2}-\dfrac{1}{2}\)

\(\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(=\dfrac{\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)}{2}\)

\(=\dfrac{3^{32}-1}{2}\)

15 tháng 10 2023

\(4\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(=\dfrac{1}{2}\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(=\dfrac{1}{2}\left(3^4-1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(=\dfrac{1}{2}\left(3^8-1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(=\dfrac{1}{2}\left(3^{16}-1\right)\cdot\left(3^{16}+1\right)\)

\(=\dfrac{1}{2}\left(3^{32}-1\right)\)

25 tháng 9 2021

a) \(A=\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)=\dfrac{1}{2}\left(3-1\right)\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)=\dfrac{1}{2}\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)=\dfrac{1}{2}\left(3^{32}-1\right)< 3^{32}-1=B\)

b) \(A=2011.2013=\left(2012-1\right)\left(2012+1\right)=2012^2-1< 2012^2=B\)

DT
8 tháng 11 2023

\(A=8.\left(3^2+1\right)\left(3^4+1\right)....\left(3^{16}+1\right)\\ =\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)....\left(3^{16}+1\right)\\ =\left(3^4-1\right)\left(3^4+1\right)....\left(3^{16}+1\right)\\ =\left(3^8-1\right)....\left(3^{16}+1\right)\\ =\left(3^{16}-1\right)\left(3^{16}+1\right)\\ =3^{32}-1\)

8 tháng 11 2023

A = 8.(3² + 1)(3⁴ + 1)(3⁸ + 1)(3¹⁶ + 1)

= (3² - 1)(3² + 1)(3⁴ + 1)(3⁸ + 1)(3¹⁶ + 1)

= (3⁴ - 1)(3⁴ + 1)(3⁸ + 1)(3¹⁶ + 1)

= (3⁸ - 1)(3⁸ + 1)(3¹⁶ + 1)

= (3¹⁶ - 1)(3¹⁶ + 1)

= 3³² - 1

22 tháng 10 2020

a) Ta có : 2005.2007 = (2006 - 1)(2006 + 1) = 20062 - 12 = 20062 - 1 ( cái khúc này sửa : 2005.2001 thành 2005.2007)

Mà B = 20062

=> 20062 - 1 < 20062 

=> A < B

b) Ta có : B = (2 + 1)(22 + 1)(24 + 1)(28 + 1)(216 + 1)

                B =  (2 - 1)(2 + 1)(22 + 1)(24 + 1)(28 + 1)(216 + 1)

                B = (22 - 1)(22 + 1)(24 + 1)(28 + 1)(216 + 1)

                B = (24 - 1)(24 + 1)(28 + 1)(216 + 1)

                B = (28 - 1)(28 + 1)(216 + 1) = (216 - 1)(216 + 1) = 232 - 1

Mà C = 232

=> B < C 

c) Tương tự như câu b

a) (+33) - (-46) + (-32) - (+15)                         b) (-54) + (+39) - (+10) + (-85)                        c) (-34) + (-84) - (-54) + (-1)                            Bài 4: Tính nhanh:a) (1267 - 196) - (267+304)                                      b) (3965-2378) - (437-1378) - 528                            Bài 5: Tìm xa) 3 - (17-x) = -12                                            b) -26 - (x-7) = 0                                              c) 25 + (-2+x) =...
Đọc tiếp

a) (+33) - (-46) + (-32) - (+15)                         

b) (-54) + (+39) - (+10) + (-85)                        

c) (-34) + (-84) - (-54) + (-1)                            

Bài 4: Tính nhanh:

a) (1267 - 196) - (267+304)                                      

b) (3965-2378) - (437-1378) - 528                            

Bài 5: Tìm x

a) 3 - (17-x) = -12                                            

b) -26 - (x-7) = 0                                              

c) 25 + (-2+x) = 5                                            

d) 30+ (32-x) = 10                                           

Bài 6. Tính:

a) (35-15). (-4) + 24.(-13-17)                                    

b) (-13).(57-34) + 57. (13-45)  

giải hộ mình nha mình đang cần gấp trong hn ;-;

1

Bài 4: 

a: =1267-196-267-304

=1000-500=500

14 tháng 8 2023

1.

a.\(A=1+2^1+2^2+2^3+...+2^{2007}\)

\(2A=2+2^2+2^3+....+2^{2008}\)

b. \(A=\left(2+2^2+2^3+...+2^{2008}\right)-\left(1+2^1+2^2+..+2^{2007}\right)\)

\(=2^{2008}-1\) (bạn xem lại đề)

 

2.

\(A=1+3+3^1+3^2+...+3^7\)

a. \(2A=2+2.3+2.3^2+...+2.3^7\)

b.\(3A=3+3^2+3^3+...+3^8\)

\(2A=3^8-1\)

\(=>A=\dfrac{2^8-1}{2}\)

 

3

.\(B=1+3+3^2+..+3^{2006}\)

a. \(3B=3+3^2+3^3+...+3^{2007}\)

b. \(3B-B=2^{2007}-1\)

\(B=\dfrac{2^{2007}-1}{2}\)

 

4.

Sửa: \(C=1+4+4^2+4^3+4^4+4^5+4^6\)

a.\(4C=4+4^2+4^3+4^4+4^5+4^6+4^7\)

b.\(4C-C=4^7-1\)

\(C=\dfrac{4^7-1}{3}\)

 

5.

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

\(2S=2+2^2+2^3+2^4+...+2^{2018}\)

\(S=2^{2018}-1\)

4:

a:Sửa đề: C=1+4+4^2+4^3+4^4+4^5+4^6

=>4*C=4+4^2+...+4^7

b: 4*C=4+4^2+...+4^7

C=1+4+...+4^6

=>3C=4^7-1

=>\(C=\dfrac{4^7-1}{3}\)

5:

2S=2+2^2+2^3+...+2^2018

=>2S-S=2^2018-1

=>S=2^2018-1