\(B=1+2+2^2+...+2^6.\)

\(=>4B=2^2+2^3+...+2^8\)\(\left(1\right)\)

\(A=2^2+2^3+...+2^8\)\(\left(2\right)\)

Từ (1) và (2) 

=> A = 4B

a. \(A=2+2^2+2^3+2^4+2^5+...+2^{200}\)

\(2A=2^2+2^3+2^4+2^5+2^6+...+2^{201}\)

\(2A-A=2^{201}-2\)

b. \(Tacó:2^1=2;2^2=4;2^3=8;2^4=..6;2^5=2;2^6=4;...\)

Cứ dựa theo quy luật trên, ta có:

\(2^{4k+1}=..2;2^{4k+2}=...4;2^{4k+3}=...8;2^{4k}=..6\)

\(=>2^{201}=2^{4.50+1}\)

\(=>2^{101}=...2\)

\(=>2^{201}-2=..2-2\)\(=0\)

Vậy A có tân cùng là 0

4+\(2^2\)+\(2^3\)+\(2^4+2^{2008}\)=\(2^2+2^2+2^3+2^4+2^{2008}\)=\(2^{2+2+3+4+2008}\)=\(2^{2020}\)

4 + 2² + 2³ + 2⁴ + 2²⁰⁰⁸

= 2² + 2² + 2³ + 2⁴ + 2²⁰⁰⁸

Thế thôi, mình không biết làm gì nữa

=4+4+8+16+2008.2008

=8+16+2008.2008

=25+2008.2008

=.........(tự làm được chưa)

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a = 2 + 2² + 2³ + ... + 2⁶⁰

2a = 2 . 2 + 2² . 2 + 2³ . 2  + ... + 2⁶⁰ . 2

2a =  2² + 2³ + 2⁴ +  ... + 2⁶¹

2a - a = 2⁶¹ - 2

a = 2⁶¹ - 2

Vậy : a = 2⁶¹ - 2

tui ko bít =))))

a) 2

b) 8

 a) 26- 3(X+1)  = 17

          3(X+1)  =  26 - 17

           3(X+1) =   9

              X+1  = 9: 3

              X+1   =  3

               X      =  3- 1

        Vậy:X      =2

 b) 5X -8 =  2³. 2²

     5X - 8 = 8 .  4

     5X  - 8 = 32

        5X    =32+8

         5X   =    40

           X   =  40 :5

    Vậy  X   =  8

 Trung Thu vui vẻ nha mn

a:2

b:8

chuc trung thu vui ve nha

\(S=\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+....+\frac{1}{2^{20}}\)

=>  \(2S=1+\frac{1}{2}+\frac{1}{2^2}+....+\frac{1}{2^{19}}\)

=>  \(2S-S=\left(1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{19}}\right)-\left(\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{20}}\right)\)

=>  \(S=1-\frac{1}{2^{20}}\)

muộn mất rồi nhưng dù sao cũng cảm ơn bạn