A = 1/3 + 1/6 + 1/12 + 1/24 + 1/48 + 1/96 + 1/192 + 1/384 + 1/768 +1/1536
Tìm x biết
X*(3+6+12+24+48+96+192+384+768+1536)= 3069
1/3 + 1/6 + 1/12 + 1/24 + 1/48 + 1/96 + 1/192 + 1/384 =
1/3 + 1/6 + 1/12 + 1/24 + 1/48 + 1/96 + 1/192 + 1/384 = 85/128
1/3+1/6+1/12+1/24+1/48+1/96+1/192+1/384
a) A=1+1/5+1/25+1/125+1/625+...+1/78125
b)B=1/3+1/12+1/48+1/192+1/768+...+1/36864
c)C=5/3+5/6+5/12+5/24...+5/192+5/384
GIÚP MÌNH VỚI XIN MỌI NGƯỜI AI GIÚP MÌNH THÌ MÌNH CHO TICK LÀM TẤT CẢ MỌI THỨ
tinh nhanh 1/3+1/6+1/12+1/24+1/48+1/96+1/192+1/384
ghi ro loi giai
Tính tổng :
a, 1/6 + 1/12 + 1/24 + 1/48 + 1/96 + 1/192 + 1/ 384
b, 1/4x7 + 1/7x10 + 1/10x13 +...........+ 1/19x22
\(a,\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+....+\frac{1}{384}\)
\(\text{Đ}\text{ặt}\)\(A=\frac{1}{6}+\frac{1}{12}+\frac{1}{24}+...+\frac{1}{384}\)
\(2A=\frac{1}{3}+\frac{1}{6}+\frac{1}{12}+....+\frac{1}{192}\)
\(2A-A=\frac{1}{3}-\frac{1}{384}\)
a đề sai
b)Đặt A=1/4x7 + 1/7x10 + 1/10x13 +...........+ 1/19x22
\(3A=3\left(\frac{1}{4.7}+\frac{1}{7.10}+...+\frac{1}{19.22}\right)\)
\(3A=\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{19}-\frac{1}{22}\)
\(3A=\frac{1}{4}-\frac{1}{22}\)
\(A=\frac{9}{44}:3\)
\(A=\frac{3}{44}\)
A=1/3 + 1/6 + 1/12 +1/24 + ............+ 1/768 + 1/1536
1/3+1/6+1/12+1/24+....+1/768+1/1536
1/3+1/6+1/12+1/24+....+1/768+1/1536
\(A=\dfrac{1}{3}\left(1+\dfrac{1}{2}+...+\dfrac{1}{256}+\dfrac{1}{512}\right)\)
Đặt B=1+1/2+...+1/256+1/512
=>2B=2+1+...+1/128+1/256
=>B=2-1/512=1023/512
=>\(A=\dfrac{1}{3}\cdot\dfrac{1023}{512}=\dfrac{341}{512}\)