\(A=\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+\frac{1}{3^4}+\frac{1}{3^5}+\frac{1}{3^6}\)
\(3A=1+\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+\frac{1}{3^4}+\frac{1}{3^5}\)
=> \(2A=1-\frac{1}{3^6}\)
=> \(A=\frac{1-\frac{1}{3^6}}{2}=\frac{729-1}{729}.\frac{1}{2}=\frac{728}{729.2}=\frac{364}{729}\)
Tính nhanh : 1/3 + 1/9 + 1/27 + 1/81 + 1/243 + 1/729
Tính nhanh:
1 + 1/3 + 1/9 + 1/27 + 1/81 + 1/243 + 1/729
1/3+1/9+1/27+1/81+1/243+1/729
tính kết quả của dãy tính sau: 1+1/3+1/9+1/27+1/81+1/243+1/729=?
\(A=1+\dfrac{1}{3}+\dfrac{1}{9}+\dfrac{1}{27}+\dfrac{1}{81}+\dfrac{1}{243}+\dfrac{1}{729}\)
Tính A
Tính nhanh:
1+ 1/3 + 1/9 + 1/27 + 1/81 + 1/243 + 1/729
1/3 + 1/9 + 1/27+1/81 + 1/243+ 1/729.
1/3+1/9+1/27+1/81+1/243+1/729 =?
1/3+1/9+1/27+1/81+1/243+1/729
Tính bằng cách thuận tiện nhất:
A = 1/3+ 1/9+ 1/27+ 1/81+ 1/243+ 1/729
