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\(a,\Rightarrow2A=2+2^2+...+2^{2011}\)
\(\Rightarrow2A-A=2+2^2+...+2^{2011}-2^0-2-..-2^{2010}\)
\(\Rightarrow A=2^{2011}-1=B\)
\(b,A=2019.2011=\left(2010-1\right)\left(2010+1\right)=\left(2010-1\right).2010+\left(2010-1\right)=2010^2-2010+2010-1=2010^2-1< 2010^2=B\)
\(a,\Rightarrow2A=2^1+2^2+...+2^{2011}\\ \Rightarrow2A-A=A=2^{2011}-2^0=2^{2011}-1=B\)
\(b,A=\left(2010-1\right)\left(2010+1\right)=2010^2+2010-2010-1=2010^2-1< 2010^2=B\)
A = 2⁰ + 2¹ + 2² + 2³ + ... + 2²⁰¹⁰
⇒ 2A = 2 + 2² + 2³ + 2⁴ + ... + 2²⁰¹¹
⇒ A = 2A - A = (2 + 2² + 2³ + 2⁴ + ... + 2²⁰¹¹) - (2⁰ + 2¹ + 2² + 2³ + ... + 2²⁰¹⁰)
= 2²⁰¹¹ - 2⁰
= 2²⁰¹¹ - 1
= B
Vậy A = B
a) A = 2⁰ + 2¹ + 2² + 2³ + ... + 2²⁰²²
2A = 2 + 2² + 2³ + 2⁴ + ... + 2²⁰²³
A = 2A - A
= (2 + 2² + 2³ + 2⁴ + ... + 2²⁰²³) - (2⁰ + 2¹ + 2² + 2³ + ... + 2²⁰²²)
= 2²⁰²³ - 2⁰
= 2²⁰²³ - 1
Vậy A = B
b) A = 2021 . 2023
= (2022 - 1).(2022 + 1)
= 2022.(2022 + 1) - 2022 - 1
= 2022² + 2022 - 2022 - 1
= 2022² - 1 < 2022²
Vậy A < B
Bài 1:
\(a,A=\left(2+2^2\right)+\left(2^3+2^4\right)+...+\left(2^{2009}+2^{2010}\right)\\ A=\left(1+2\right)\left(2+2^3+...+2^{2009}\right)=3\left(2+...+2^{2009}\right)⋮3\\ A=\left(2+2^2+2^3\right)+...+\left(2^{2008}+2^{2009}+2^{2010}\right)\\ A=\left(1+2+2^2\right)\left(2+...+2^{2008}\right)=7\left(2+...+2^{2008}\right)⋮7\)
\(b,\left(\text{sửa lại đề}\right)B=\left(3+3^2\right)+\left(3^3+3^4\right)+...+\left(3^{2009}+3^{2010}\right)\\ B=\left(1+3\right)\left(3+3^3+...+3^{2009}\right)=4\left(3+3^3+...+3^{2009}\right)⋮4\\ B=\left(3+3^2+3^3\right)+...+\left(3^{2008}+3^{2009}+3^{2010}\right)\\ B=\left(1+3+3^2\right)\left(3+...+3^{2008}\right)=13\left(3+...+3^{2008}\right)⋮13\)
Bài 2:
\(a,\Rightarrow2A=2+2^2+...+2^{2012}\\ \Rightarrow2A-A=2+2^2+...+2^{2012}-1-2-2^2-...-2^{2011}\\ \Rightarrow A=2^{2012}-1>2^{2011}-1=B\\ b,A=\left(2020-1\right)\left(2020+1\right)=2020^2-2020+2020-1=2020^2-1< B\)
\(a.10^{30}=\left(10^3\right)^{10}=1000^{10}\\ 2^{100}=\left(2^{10}\right)^{10}=1024^{10}\)
Vì 100010 < 102410 => 1030 < 2100
\(b,333^{444}=\left(111\cdot3\right)^{444}=111^{444}\cdot3^{444}=111^{444}\cdot81^{111}\\ 444^{333}=\left(111\cdot4\right)^{333}=111^{333}\cdot4^{333}=111^{333}\cdot64^{111}\)
Vì 111444 >111333 ; 81111 > 64111 => 333444 > 444333
Ta có :
\(A=2+2^2+2^3+2^4...2^{2010}\)\(^0\)
\(=2\left(1+2\right)+2^3\left(1+2\right)+...+2^{2009}\left(1+2\right)\)
\(=2.3+2^3.3+....+2^{2009}.3\)
\(=3\left(2+2^3+....+2^{2009}\right)⋮3\)
Ta có :
\(2+2^2+2^3+2^4+....+2^{2010}\)
\(=2\left(1+2+2^2\right)+2^4\left(1+2+2^2\right)+...+2^{2008}\left(1+2+2^2\right)\)
\(=2.7+2^4.7+....+2^{2008}.7\)
\(=7\left(2+2^4+....+2^{2008}\right)⋮7\)
Vậy \(2^1+2^2+2^3+2^4+...+2^{2010}⋮3\) và \(7\)
2010^2 và 2009.2011
<=> (2009+1).2010 và 2009.(2010+1)
<=> 2009.2010+2010 > 2009.2010+2009
b) phân tích 2^16 - 1 ta được
2^16-1=(2^8+1)(2^4+1)(2^2+1)(2^2-1)=A
Vậy B>A
tick mik đi rùi mik làm típ câu b cho !!!
\(A=\left(\frac{20}{5}+\frac{27}{9}\right)\times\frac{21}{10}=\left(4+3\right)\times\frac{21}{10}=7\times\frac{21}{10}=\frac{147}{10}\)
\(B=\left(\frac{13}{6}-\frac{3}{8}\right)\times\frac{11}{22}\)
\(B=\left(\frac{52}{24}-\frac{9}{24}\right)\times\frac{11}{22}\)
\(B=\frac{43}{24}\times\frac{1}{2}=\frac{43}{48}\)
Dễ thấy \(A=\frac{147}{10}>1\)
Mà \(B=\frac{43}{48}< 1\)
=> tự so sánh
a, \(A=2^0+2^1+2^2+...+2^{2010}\)
\(\Leftrightarrow2A=2^1+2^2+2^3+...+2^{2011}\)
\(\Leftrightarrow2A-A=A=2^{2011}-2^0=2^{2011}-1\)
\(\Rightarrow A=B\)
b, \(B=2010^2=2010\times2010\)
Ta có : \(2009\times2011=2009\times\left(2010+1\right)=2009\times2010+2009\)
\(2010\times2010=2010\times\left(2009+1\right)\)\(=2010\times2009+2010\)
Vì \(2009< 2010\)
\(\Rightarrow A< B\)
c , Ta có : \(A=333^{444}=\left(333^4\right)^{111}\)
\(B=444^{333}=\left(444^3\right)^{111}\)
Cả A và B đều có cùng số mũ 111 nên ta so sánh \(333^4\)và \(444^3\)
Ta thấy : \(333^4=\left(3\times111\right)^4=3^4\times111^4=81\times111^4\)
\(444^3=\left(4\times111\right)^3=4^3\times111^3=64\times111^3\)
Vì \(81\times111^4>64\times111^3\)
\(\Rightarrow A>B\)
d , Ta có : \(A=10^{30}=\left(10^3\right)^{10}=1000^{10}\)
\(B=2^{100}=\left(2^{10}\right)^{10}=1024^{10}\)
\(\Rightarrow B>A\)
e , Ta có : \(A=3^{450}=\left(3^9\right)^{50}=19683^{50}\)
\(B=5^{300}=\left(5^6\right)^{50}=15625^{50}\)
\(\Rightarrow A>B\)
_Chúc bạn học tốt_
a) Ta có :
A = 20 + 2 + 22 + ... + 22010
2A = 2 + 22 + 23 + ... + 22011
2A - A = ( 2 + 22 + 23 + ... + 22011 ) - ( 20 + 2 + 22 + ... + 22010 )
A = 22011 - 20 = 22011 - 1 = B
b) A = 2009 . 2011 = ( 2010 - 1 ) . 2011 = 2010 . 2011 - 2011
B = 20102 = 2010 . 2010 = ( 2011 - 1 ) . 2010 = 2011 . 2010 - 2010
Ta thấy 2010 . 2011 - 2011 < 2011 . 2010 - 2010 nên A < B
c) Ta có : 333444 = ( 3334 )111 ; 444333 = ( 4443 )111
Lại có : 3334 = ( 3 . 111 )4 = 34 . 1114 = 81 . 1114 ; 4443 = ( 4 . 111 )3 = 43 . 1113 = 64 . 1113
Ta thấy 81 . 1114 > 64 . 1113 nên A > B
d) A = 1030 = ( 103 )10 = 100010 ; B = 2100 = ( 210 )10 = 102410
vì 100010 < 102410 nên A < B
e) A = 3450 = ( 33 )150 = 27150
B = 5300 = ( 52 )150 = 25150
vì 27150 > 25150 nên A > B