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30 tháng 4 2021
Đặt A=1+2+22+...+220081+2+22+...+22008
=>2A=2.(1+2+22+...+220081+2+22+...+22008)
=>2A=2+22+23+...+220092+22+23+...+22009
=>2A-A=(2+22+23+...+220092+22+23+...+22009)-(1+2+22+...+220081+2+22+...+22008)
=>A=22009−122009−1
=>A=(-1).(−2)2009(−2)2009+(-1).1
=>A=(-1).[(−2)2009+1][(−2)2009+1]
=>A=(-1).(1−22009)(1−22009)
=>1+2+22+...+220081+2+22+...+22008/1-2200922009
=(−1).(1−22009)1−22009(−1).(1−22009)1−22009=-1
30 tháng 4 2021
Giải:
Đặt A=1+2+22+23+...+22008
2A=2+22+23+24+...+22009
2A-A=(1+2+22+23+...+22008)-(2+22+23+24+...+22009)
A =1-22009
Vậy B=1-22009/1-22009=1
Chúc bạn học tốt!
KV
22 tháng 10 2023
a) P = 1 + 3 + 3² + ... + 3¹⁰¹
= (1 + 3 + 3²) + (3³ + 3⁴ + 3⁵) + ... + (3⁹⁹ + 3¹⁰⁰ + 3¹⁰¹)
= 13 + 3³.(1 + 3 + 3²) + ... + 3⁹⁹.(1 + 3 + 3²)
= 13 + 3³.13 + ... + 3⁹⁹.13
= 13.(1 + 3³ + ... + 3⁹⁹) ⋮ 13
Vậy P ⋮ 13
b) B = 1 + 2² + 2⁴ + ... + 2²⁰²⁰
= (1 + 2² + 2⁴) + (2⁶ + 2⁸ + 2¹⁰) + ... + (2²⁰¹⁶ + 2²⁰¹⁸ + 2²⁰²⁰)
= 21 + 2⁶.(1 + 2² + 2⁴) + ... + 2²⁰¹⁶.(1 + 2² + 2⁴)
= 21 + 2⁶.21 + ... + 2²⁰¹⁶.21
= 21.(1 + 2⁶ + ... + 2²⁰¹⁶) ⋮ 21
Vậy B ⋮ 21
c) A = 2 + 2² + 2³ + ... + 2²⁰
= (2 + 2² + 2³ + 2⁴) + (2⁵ + 2⁶ + 2⁷ + 2⁸) + ... + (2¹⁷ + 2¹⁸ + 2¹⁹ + 2²⁰)
= 30 + 2⁴.(2 + 2² + 2³ + 2⁴) + ... + 2¹⁶.(2 + 2² + 2³ + 2⁴)
= 30 + 2⁴.30 + ... + 2¹⁶.30
= 30.(1 + 2⁴ + ... + 2¹⁶)
= 5.6.(1 + 2⁴ + ... + 2¹⁶) ⋮ 5
Vậy A ⋮ 5
d) A = 1 + 4 + 4² + ... + 4⁹⁸
= (1 + 4 + 4²) + (4³ + 4⁴ + 4⁵) + ... + (4⁹⁷ + 4⁹⁸ + 4⁹⁹)
= 21 + 4³.(1 + 4 + 4²) + ... + 4⁹⁷.(1 + 4 + 4²)
= 21 + 4³.21 + ... + 4⁹⁷.21
= 21.(1 + 4³ + ... + 4⁹⁷) ⋮ 21
Vậy A ⋮ 21
e) A = 11⁹ + 11⁸ + 11⁷ + ... + 11 + 1
= (11⁹ + 11⁸ + 11⁷ + 11⁶ + 11⁵) + (11⁴ + 11³ + 11² + 11 + 1)
= 11⁵.(11⁴ + 11³ + 11² + 11 + 1) + 16105
= 11⁵.16105 + 16105
= 16105.(11⁵ + 1)
= 5.3221.(11⁵ + 1) ⋮ 5
Vậy A ⋮ 5
PT
1
PT
1
CM
24 tháng 8 2019
A = 1 + 2 + 2 2 + . . . + 2 2007
2 A = 2 + 2 2 + . . . + 2 2007 + 2 2008
A = 2A - A = ( 2 + 2 2 + . . . + 2 2007 + 2 2008 ) - ( 1 + 2 + 2 2 + . . . + 2 2007 ) = 2 2008 - 1
Vậy A = 2 2008 - 1
![YTP] Huấn Hoa Hồng Chế](data:image/jpeg;base64,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)
PT
1
CM
10 tháng 3 2019
Ta có A = 2A – A = 2( 1 + 2 + 2 2 + 2 3 + . . . + 2 50 ) – ( 1 + 2 + 2 2 + 2 3 + . . . + 2 50 )
= 2 + 4 + 2 3 + 2 4 + . . . + 2 51 – ( 1 + 2 + 2 2 + 2 3 + . . . + 2 50 )
= 6 + 2 3 + 2 4 + . . . + 2 51 – ( 7 + 2 3 + . . . + 2 50 ) = 2 51 - 1
Suy ra : A + 1 = 2 51
Vậy A+1 là một lũy thừa của 2
PT
1
21 tháng 12 2023
=> 2A =2 + 22 + 23 + ... + 22020
=> 2A-A =( 2 + 22 + 23 + ... + 22020)- (1 + 2 + 22 + 23 + ... + 22019)
=> A =22020-1
=> A+1 =22020
Vậy A + 1 là một số chính phương
NN
2
21 tháng 11 2021
A=\((1+2)+\left(2^2+2^3\right)+...+\left(2^{19}+2^{20}\right)\)
A=\(3.1+2^2\left(1+2\right)+...+2^{19}\left(1+2\right)\)
A=\(3.1+3.2^2+...+3.2^{19}\)
A=\(3\left(1+2^2+...+2^{19}\right)\)\(⋮3\)
Vậy A\(⋮3\)
21 tháng 11 2021
A=(1+2)+(22+23)+...+(219+220)(1+2)+(22+23)+...+(219+220)
A=3.1+22(1+2)+...+219(1+2)3.1+22(1+2)+...+219(1+2)
A=3.1+3.22+...+3.2193.1+3.22+...+3.219
A=3(1+22+...+219)3(1+22+...+219)⋮3⋮3
NÊN A⋮3
\(2A\)\(=\)\(2^2+2^3+2^4+......+2^{2009}\)
\(2A-A=\left(2+2^2+2^3+2^4+...+2^{2009}\right)-\left(1+2+2^2+2^3+...+2^{2008}\right)\)\(A=2^{2009}-1\)
\(B-A=2009-\left(2009-1\right)\)
\(B-A=1\left(ĐPCM\right)\)