Ta có:
\(A=3+3^2+3^3+...+3^{2009}\)
\(3A=3^2+3^3+3^4+...+3^{2010}\)
\(3A-A=2A=\left(3^2+3^3+3^4+...+3^{2010}\right)-\left(3+3^2+3^3+...+3^{2009}\right)\)
\(2A=3^{2010}-3\)
\(A=\frac{3^{2010}-3}{2}\)
Ta có:
2A + 3 = 32010 - 3 + 3 = 32010
=> n = 2010
Vậy n = 2010
ỦNG HỘ NHA
nhin ma da chong mat,huong j phai suy nghi bai bay
A=3+32+33+...+32009
3A=32+33+34+...+32010
3A-A=32010-3
2A=32010-3
2A+3=32010
=>n=2010
3A=3^(2+3^(3+3^(4+.....+3^(2010
2A=3^(2010-3
ma co : 3^(2010-3+3=3^(n
Vay n bang 2010
