a) \(A=2^0+2^1+2^2+...+2^{2010}\)
\(\Rightarrow2A=2^1+2^2+2^3+...+2^{2011}\)
\(\Rightarrow2A-A=\left(2^1+2^2+2^3+...+2^{2011}\right)-\left(2^0+2^1+2^2+...+2^{2010}\right)\)
\(\Rightarrow A=2^{2011}-2^0\)
\(\Rightarrow A=2^{2011}-1\)
Vì \(2^{2011}-1=2^{2011}-1\) nên \(A=B\)
Vậy A = B
b) Ta có: \(A=2009.2011=2009.\left(2010+1\right)=2009.2010+2009\)
\(B=2010^2=\left(2009+1\right).2010=2009.2010+2010\)
Vì \(2009.2010+2009< 2009.2010+2010\) nên A < B
Vậy A < B
\(A=2^0+2^1+2^2+2^3+....+2^{2010}\)
\(2.A=2\left(2^0+2^1+2^2+2^3+....+2^{2010}\right)\)
\(2.A=2.2^0+2.2+2.2^2+2.2^3+....+2.2^{2010}\)
\(2.A=2+2^2+2^3+2^4+....+2^{2011}\)
\(2A-A=\left(2+2^2+2^3+2^4+....+2^{2011}\right)-\left(2^0+2^1+2^2+2^3+....+2^{2010}\right)\)
\(A=\left(2-2^1\right)+\left(2^2-2^2\right)+\left(2^3-2^3\right)+....+\left(2^{2010}-2^{2010}\right)+2^{2011}-2^0\)
\(A=0+0+0+....+0+2^{2011}-2^0\)
\(A=2^{2011}-2^0\)
\(A=2^{2011}-1\)
Vì \(A=2^{2011}-1\) ; \(B=2^{2011}-1\)
\(=>A=B\)
Vậy \(A=B\)
b) \(A=2009.2001\)
\(A=\left(2010-1\right)\left(2010+1\right)\)
\(A=\left(2010-1\right).2010+\left(2010-1\right).1\)
\(A=2010.2010-2010.1+1.2010-1.1\)
\(A=2010^2-2010+2010-1\)
\(A=2010^2+0-1\)
\(A=2010^2-1\)
Vì \(A=2010^2-1\) ; \(B=2010^2\)
\(=>A< B\)
Vậy \(A< B\)
