1, 456.999 tinh nhanh 2,321.9999999999
3,1+2+4+8+16+32+......+2048+4096
1+1=?
2+2=?
4+4=?
8+8=?
16+16=?
32+32=?
64+64=?
128+128=?
256+256=?
512+512=?
1024+1024=?
2048+2048=?
4096+4096=?
Giải đi
2
4
8
16
32
64
128
256
512
1024
2048
4096
8192
1+1=2
2+2=4
4+4=8
8+8=16
16+16=32
64+64=128
128+128=256
512+512=1024
2048+2048=4096
xong
1+1=2
2+2=4
4+4=8
8+8=16
16+16=32
32+32=64
64+64=128
128+128=256
256+256=512
512+512=1024
1024+1024=2048
2048+2048=4096
4096+4096=8192
1/2+1/4+1/8+1/16+1/32+...+1/2048+1/4096
Đặt A=1/2+1/4+1/8+1/16+1/32+...+1/2048+1/4096
\(A=\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{12}}\)
\(2A=2\left(\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{12}}\right)\)
\(2A=1+\frac{1}{2}+...+\frac{1}{2^{11}}\)
\(2A-A=\left(1+\frac{1}{2}+...+\frac{1}{2^{11}}\right)-\left(\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{12}}\right)\)
\(A=1-\frac{1}{2^{12}}\)
1 + 2 + 4 + 8 + 16 + 32 + ... + 1024 + 2048 + 4096 =?
KHẨN CẤP! KHẨN CẤP!
Đặt \(A=1+2+4+.........+4096\)
\(2A=2+4+8+......+8192\)
\(\Rightarrow2A-A=8192-1\)
\(\Rightarrow A=8191\)
Đặt \(S=1+2+4+...+1024+2048+4096\)
\(S=1+2^1+2^2+2^3+....+2^{10}+2^{11}+2^{12}\)
\(2S=2+2^2+2^3+....+2^{11}+2^{12}+2^{13}\)
\(2S-S=\left(2+2^2+2^3+....+2^{12}+2^{13}\right)-\left(1+2+2^2+....+2^{11}+2^{12}\right)\)
\(S=2^{13}-1=8192-1=8191\)
A=1+2+4+8+16+.....+1024+2048+4096
2A= 2+4+8+16+32+....+2048+4096+8192
2A-A=A=2+4+8+16+32+....+4096+8192-(1+2+4+8+16+...+1024+2048+4096)
A=8192-1
A=8191 k nha
Tính tổng :
A = 8 + 16 + 32 + 64 + ... + 2048 + 4096
Kết quả A=8184
Thấy đúng thì k cho mình nhé.
A=8+16+32+64+...+2048+4096
2A=8+16+32+64+...+8192
=>2A-A=8192-1
=>A=8191
số số hạng là : (4096-8):8+1=512
tổng là :A=(4096+8)x512/2=1050624
=> A=1050624
1/2+1/4+1/8+1/16+..........................+1/2048+1/4096
bn tham khảo tại link này nhé :
https://olm.vn/hoi-dap/question/656309.html
https://olm.vn/hoi-dap/question/656309.html
2+4+6+8+16+...+2048+4096
số số hạng là:
(4096 - 2) : 2 + 1 = 2048
Tổng trên là:
(4096 + 2) . 2048 : 2 = 4196352
Tính S = 1+1/2+1/4+1/8+1/16+........+1/2048+1/4096
Ta co: 2S=2+1+1/2+1/4+...+1/2048
2S-S=2+1+1/2+1/4+...+1/2048-1-1/2-1/4-...-1/2048-1/4096
\(\Rightarrow\)S=2-1/4096 =8191/4096
F=2+4+6+8+16+...+2048+4096
SSH:(4096-2):2+1=2048
Tổng:(4096+2)x2048:2=4196352
1/2 + 1/4 + 1/8 +.....+ 1024 + 2048 + 4096= ?
( Ai nhanh nhất mà đúng cho tick)
Đặt \(A=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+...+\frac{1}{1024}+\frac{1}{2048}+\frac{1}{4096}\)
\(\Leftrightarrow A=\frac{1}{2^1}+\frac{1}{2^2}+\frac{1}{2^3}+....+\frac{1}{2^{10}}+\frac{1}{2^{11}}+\frac{1}{2^{12}}\)
Nhân 2 vào 2 vế của biểu thức A , ta được :
\(2A=2\left(\frac{1}{2^1}+\frac{1}{2^2}+\frac{1}{2^3}+....+\frac{1}{2^{10}}+\frac{1}{2^{11}}+\frac{1}{2^{12}}\right)\)
\(\Rightarrow2A=1+\frac{1}{2^1}+\frac{1}{2^2}+....+\frac{1}{2^9}+\frac{1}{2^{10}}+\frac{1}{2^{11}}\)
Lấy biểu thức 2A - A , Ta được :
\(2A-A=\left(1+\frac{1}{2^1}+\frac{1}{2^2}+....+\frac{1}{2^{10}}+\frac{1}{2^{11}}\right)-\left(\frac{1}{2^1}+\frac{1}{2^2}+\frac{1}{2^3}+....+\frac{1}{2^{11}}+\frac{1}{2^{12}}\right)\)
\(\Rightarrow A=1-\frac{1}{2^{12}}\)