Đặt \(A=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+...+\frac{1}{148}+\frac{1}{256}\)
\(\Rightarrow A=\frac{1}{2^1}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^7}+\frac{1}{2^8}\)
\(\Rightarrow A=1-\frac{1}{2^7}=1-\frac{1}{128}=\frac{127}{128}\)
tính nhanh
1/2+1/4+1/8+...+1/148+1/256.
tính bằng cách thuận tiện nhất
1/3+1/6+1/12+...+1/192+1/384.
tính bằng cách hợp lý
2/1*3+2/5*7+...+2/101*99
tính A 1/2+1/4+1/8+...+1/256=a/256
1/2 + 1/4 + 1/8 ........ 1/128 + 1/256
Giúp mik
Tính nhanh:
a) 1/2 + 1/4 + 1/8 +..........+ 1/256
b) 1/1 x 2 + 1/2 x 3 + 1/3 x 4 +...............+ 1/ 13 x 14
c) 3/15 x 18 + 3/18 x 21 + 3/21 x 24 +..........+ 3/87 x 90
1/2+1/4+1/6+1/8+1/16+...+1/256+1/512 = ?
tính :
1 / 2 + 1 / 4 + 1 / 8 + ..... + 1 / 128 + 1 / 256
tính :
1 / 2 + 1 / 4 + 1 / 8 + ..... + 1 / 128 + 1 / 256
1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256
1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256 = ?
