1/3 + 1/6 + 1/12 + 1/24 + 1/48 + 1/96 + 1/192 + 1/384 = 85/128

0.6640625

85/128 nha 

\(A=\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}+\frac{1}{192}+\frac{1}{384}+\frac{1}{768}+\frac{1}{1536}\)

\(A\times2=\frac{2}{3}+\frac{2}{6}+\frac{2}{12}+\frac{2}{24}+\frac{2}{48}+\frac{2}{96}+\frac{2}{192}+\frac{2}{384}+\frac{2}{768}+\frac{2}{1536}\)

Rút gọn ta được

\(A\times2=\frac{2}{3}+\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}+\frac{1}{192}+\frac{1}{384}+\frac{1}{768}\)

\(A\times2-A=\frac{2}{3}+\frac{1}{3}+\frac{1}{6}+...+\frac{1}{768}-\left[\frac{1}{3}+\frac{1}{6}+...+\frac{1}{1536}\right]\)

\(A=\frac{2}{3}+\frac{1}{3}-\frac{1}{3}-\frac{1}{1536}\)

\(A=\frac{2}{3}-\frac{1}{1536}=\frac{341}{512}\)

Bạn hiểu cách làm lớp 6 ko mk gửi

Đáp số: 341/512

= 1 - 1/96=95/96

k mk nha

  1/3+1/6+1/12+1/24+1/48+1/96

= 1x32/3x32 + 1x16/6x16 + 1x8/12x8 + 1x4/24x4 + 1x2/48x2 + 1/96

= 32/96 + 16/96 + 8/96 + 4/96 + 2/96 + 1/96

= 32 + 16 + 8 + 4 + 2 + 1 /96

= 63/96

\(a,\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+....+\frac{1}{384}\)

\(\text{Đ}\text{ặt}\)\(A=\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+...+\frac{1}{384}\)

\(2A=\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+....+\frac{1}{192}\)

\(2A-A=\frac{1}{3}-\frac{1}{384}\)

a đề sai

b)Đặt A=1/4x7 + 1/7x10 + 1/10x13 +...........+ 1/19x22

\(3A=3\left(\frac{1}{4.7}+\frac{1}{7.10}+...+\frac{1}{19.22}\right)\)

\(3A=\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{19}-\frac{1}{22}\)

\(3A=\frac{1}{4}-\frac{1}{22}\)

\(A=\frac{9}{44}:3\)

\(A=\frac{3}{44}\)

1/3+1/6+1/12+1/24+1/48+1/96=21/32

21/32

\(\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+\frac{1}{48}+\frac{1}{96}=\frac{21}{32}\)

Nhớ click cho mik nha !!!!!!!!!!!!!!!!!!!!!

1/3 + 1/6+1/12+1/24+1/48+1/96
= 2/3 – 1/3 + 1/3 – 1/6+1/6- 1/12+1/12- 1/24+1/24-
1/48+1/48-1/96
=2/3_1/96

= 63/96
= 21/32

= 1-1/3+1/3-1/6+1/6-1/12+1/12-1/24+1/24-1/48+1/48-1/96+1/96-1/192 

 = 1-1/192 = 191 / 192 

1/3 +1/6+1/12+1/24 +1/48 + 1/96
= 1/3 + 1/3 – 1/6 + 1/6 – 1/12+1/12 – 1/24 +1/24 –
1/48+1/48 -1/96
=2/3 – 1/96
= 63/96
= 21/32