A= 1/2 + 1/4+ 1/8+ 1/16 + 1/32 + 1/64 + 1/128 + 1/256 + 1/512 
A = 1 - 1/2 + 1/2- 1/4 + 1/4 - 1/8 + 1/8 - 1/16 + 1/16 - 1/32 + 1/32 - 1/64 + 1/64 - 1/128 + 1/128 - 1/256 - 1/256 - 1/512 
A = 1 - 1/512 
A = 511/512 
Chúc bạn học giỏi nha!

gọi biểu thức đó là A

A=1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256+1/512

1/512+A=1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256+1/512+1/512

1/512+A=1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256+1/256

1/512+A=1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/128

1/512+A=1/2+1/4+1/8+1/16+1/32+1/64+1/64

1/512+A=1/2+1/4+1/8+1/16+1/32+1/32

1/512+A=1/2+1/4+1/8+1/16+1/16

1/512+A=1/2+1/4+1/8+1/8

1/512+A=1/2+1/4+1/4

1/512+A=1/2+1/2

1/512+A=1

A=1-1/512

A=511/512

chắc 100%

*Tham khảo 

b-1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256

a)

\(A=2+4+8+...+2048\)

\(A=2+2^2+...+2^{11}\)

\(2A=2^2+2^3+...+2^{12}\)

\(2A-A=\left(2^2+2^3+...+2^{12}\right)-\left(2+2^2+...+2^{11}\right)\)

\(A=2^{12}-2\)

a) 2+4+8+16+32+64+128+512+1024+2048

b thì minh cha ra. Mình sẽ cố làm ra b mong ban thong cam va bạn nho k đung cho minh nha

gọi A=1/2+1/4+1/8+...+1/1024

2xA=1+1/2+1/4+.....+1/512

2xA-A=(1+1/2+1/4+....+1/512)-(1/2+1/4+1/8+...+1/1024)

A=1-1/1024

=1023/1024

vậy A=1023/1024

\(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{1024}=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{4}+...+\frac{1}{512}-\frac{1}{1024}=1-\frac{1}{1024}=\frac{1023}{1024}\)

đặt  biểu thức là A ta có :

 A = 1/2 + 1/4  + 1/8 + 1/16 +1/32 +1/64 +1/128 + 1/256 + 1/512 + 1/102

A x 2 = 1+ 1/2 + 1/4 + 1/8 + 1/16 +1 /32+1/64 + 1/ 128 + 1/256 + 1/512 

A = ( 1 + 1/2 +1/4 + 1/ 8+ 1/16 + 1/32 + 1/64 + 1/128 + 1/256 + 1/512 ) - ( 1/2 + 1/4 + 1/8 +1/16 +1/32 + 1/64 + 1/128 +1/256 +1/512 +1/1024)

A = 1 - 1/1024 

A = 1023/1024

nhớ k nhé

(1 / 2) + (1 / 4) + (1 / 8) + (1 / 16) + (1 / 32) + (1 / 64) + (1 / 128) + (1 / 256) + (1 / 512) + (1 / 1024) =

0.9990234375

\(M=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+...+\frac{1}{512}\)

\(2M=1+\frac{1}{2}+\frac{1}{4}+...+\frac{1}{256}\)

\(2M-M=\left(1+\frac{1}{2}+\frac{1}{4}+...+\frac{1}{256}\right)-\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+...+\frac{1}{512}\right)\)

\(M=1-\frac{1}{512}=\frac{511}{512}\)

a, 1+2+4+8+16+32+...+256+512+1024

= 2⁰+2¹+2²+2³+2⁴+2⁵+...+2⁸+2⁹+2¹⁰

= 1 + 2 + 2^{2+3+4+5+...+8+9+10}

= 3+2⁵⁴

a lấy 2+8 + 4+16+......

b lấy 1+9+4+16+...