Đặt A = 1/2 + 1/4 + 1/8 + ... + 1/1024

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

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

A = 1 - 1/1024

A = 1023/1024

mk ko hieu cho lam

\(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+...+\frac{1}{1024}\)

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{8}+\frac{1}{8}-\frac{1}{16}+\frac{1}{16}-\frac{1}{32}+...+\frac{1}{1024}\)

\(=1-\frac{1}{1024}\)

\(=\frac{1023}{1024}\)

uyjbiyjhnbgyhgyuihyygbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb

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

Đặt \(A=1-\frac{1}{2}-\frac{1}{4}-\frac{1}{8}-..-\frac{1}{2048}\)

\(\Rightarrow A=1-\left(1-\frac{1}{2}\right)-\left(\frac{1}{2}-\frac{1}{4}\right)-..-\left(\frac{1}{1024}-\frac{1}{2048}\right)\)

\(\Rightarrow A=1-1+\frac{1}{2}-\frac{1}{2}+\frac{1}{4}-..-\frac{1}{1024}+\frac{1}{2018}\)

\(\Rightarrow A+\frac{1}{2018}\)

1-1/2-1/4-1/8-1/16-1/32-1/64-1/128-1/256-1/512-1/1024-1/2048 =0.00048828125

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 tổng trên là A. Ta có

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

Ax2 - 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+ 1/2 +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 = 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

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

a*2=1+1/2+1/4+1/8+1/16+...+1/512

a*2-a=1+1/2+1/4+...+1/512-1/2-1/4-1/8-/...-1/1024

a=1-1/1204

a=1023/1024