A = 1/2 + 1/4 + 1/8 +...+ 1/512 + 1/1024
lam vay co duoc ko
1/2+1/4+1/8+... +1/512+1/1024=1-1/2+1/2-1/4+...+1/512-1/1024=1-1/1024=1/1023
kết quả sai rồi phải là \(\frac{1023}{1024}\)
làm vậy cũng dc nhưng kết quả phải là \(\frac{1023}{1024}\) hén
A=1/2+1/4+1/8+...+1/512+1/1024
Mk lm tắt nha
Hk bik có đúng hk nữa
A= 1/2-1/12024
.... Tự tính kết quả nha
gọi A = 1/2+1/4+1/8+......+1/1024 2 x A = 1 + 1/2 + 1/4+......+1/1024 2 x A - 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
trả lời
A =1023/1024
chúc bn
hc tốt
a=1/2+1/4+1/8 . . . +1/512+1/1024.
= \(\frac{1023}{1024}\)nha ban
k minh nha
a=1/2 +1/4+1/8+.....+1/512+1/1024
A = 1 - 1/2 + 1/2 - 1/4 + 1/4 - 1/8 + ..... + 1/256 - 1/512 + 1/512 - 1/1024
A = 1 - 1/1024
A = 1023/1024
A = \(\frac{1}{2}\)+ \(\frac{1}{4}\)+ \(\frac{1}{8}\)+ .....+\(\frac{1}{512}\)+\(\frac{1}{1024}\)
Gấp biểu thức A lên 2 lần ta có :
A x 2 = (\(\frac{1}{2}\)+ \(\frac{1}{4}\)+ \(\frac{1}{8}\)+ .....+ \(\frac{1}{512}\)+ \(\frac{1}{1024}\)) x 2
A x 2 = \(\frac{1x2}{2}\)+ \(\frac{1x2}{4}\)+ \(\frac{1x2}{8}\)+.....+ \(\frac{1x2}{512}\)+ \(\frac{1x2}{1024}\)
A x 2 = \(1\)+ \(\frac{1}{2}\)+\(\frac{1}{4}\)+....+\(\frac{1}{256}\)+\(\frac{1}{512}\)
A x (2 - 1)= 1 + \(\frac{1}{2}\)+\(\frac{1}{4}\)+ ....+ \(\frac{1}{256}\)+ \(\frac{1}{512}\)- \(\frac{1}{2}\)-\(\frac{1}{4}\)-\(\frac{1}{8}\)-......- \(\frac{1}{512}\)-\(\frac{1}{1024}\)
A = \(1\)- \(\frac{1}{1024}\)
A = \(\frac{1024}{1024}\)- \(\frac{1}{1024}\)
A = \(\frac{1023}{1024}\)
A=1/2+1/4+1/8+.....+1/512+1/1024
Ta có: A=1/2 + 1/4 + 1/8 +...+ 1/512 + 1/1024 2A= 1+ 1/2 + 1/4+...+1/256+1/512 2A - A=(1+1/2+1/4+...+1/256+1/512) - ( 1/2+1/4+1/8+...+1/512+1/1024) suy ra A= 1 - 1/1024= 1023/1024 . Vậy A = 1023/1024. nhớ chọn câu trả lời của mình nha!
\(A=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+....+\frac{1}{512}+\frac{1}{1024}\)
Đặt tổng trên là A , ta có :
\(A\times2=\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+...+\frac{1}{512}+\frac{1}{1024}\right)\)
\(A\times2=\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+...+\frac{1}{512}+\frac{1}{1024}\right)\times2\)
\(A\times2=\frac{1}{2}\times2+\frac{1}{4}\times2+\frac{1}{8}\times2+...+\frac{1}{512}\times2+\frac{1}{1024}\times2\)
\(A\times2=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+...+\frac{1}{512}+\frac{1}{1024}\)
\(A\times2-A=\left(1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+...+\frac{1}{512}+\frac{1}{1024}\right)-\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+...+\frac{1}{512}+\frac{1}{1024}\right)\)
\(A=\left(1-\frac{1}{1024}\right)+\left(\frac{1}{2}-\frac{1}{2}\right)+\left(\frac{1}{4}-\frac{1}{4}\right)+\left(\frac{1}{8}-\frac{1}{8}\right)+....+\left(\frac{1}{256}-\frac{1}{256}\right)+\left(\frac{1}{1024}-\frac{1}{1024}\right)\)
\(A=\frac{1023}{1024}\)
Nguyễn Linh Chi : Mong cô check bài này cho em ạ !!
A=1/2+1/4+1/8+1/16+.........+1/512+1/1024 = ?
Đặt S = 1/2 + 1/4 + 1/8 + 1/16 + ...
==> 2S = 1 + 1/2 + 1/4 + 1/8 + 1/16 + ...
2S = 1 + S
==> S = 1
Ta có 2xA=1+1/2+...+1/512
Do đó: A=2xA-A=1-1/1024=1023/1024.
A=1/2+1/4+1/8+....+1/512+1/1024
A=\(\dfrac{1}{2}\)+\(\dfrac{1}{4}\)+\(\dfrac{1}{8}\)+....+\(\dfrac{1}{512}\)+\(\dfrac{1}{1024}\)
\(A=\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+...+\dfrac{1}{512}+\dfrac{1}{1024}\)
\(=\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{10}}\)
\(\Rightarrow2A=1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^9}\)
\(\Rightarrow2A-A=A=1-\dfrac{1}{2^{10}}\)
1/2+1/4+1/8+...+1/512+1/1024
=1-(1/2+1/2-1/4+1/4-1/8+1/8...-1/1024+1/1024-1/1024)
=1-1/1024
=1023/1024
\(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+...+\frac{1}{512}+\frac{1}{1024}\)
\(=1-\frac{1}{1024}\)
\(=\frac{1024}{1024}-\frac{1}{1024}\)
\(=\frac{1023}{1024}\)
1/2+1/4+1/8+.....+1/512+1/1024
=>1-1/2+1/2-1/4+1/4-1/8+......+1/152-1/1024
=>1-1/1024
=>1023/1024