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M=22010-(22009+22008+22007+...+21+20)
M=22010-22009-22008-22007-...-21-20
=>2M=22011-22010-22009-22008-...-22-21
=>2M-M=22011-22010-22009-22008-...-22-21-(22010-22009-22008-22007-...-21-20)
=>M=22011-22010-22009-22008-...-22-21-22010+22009+22008+22007+...+21+20
=22011-22010-22010+20
=22011-2.22010+1
=22011-22011+1
=1
Vậy M=1
\(M=2^{2010}-\left(2^{2009}+2^{2008}+....+2+1\right)\)
Đặt :
\(A=2^{2008}+2^{2007}+........+2+1\)
\(\Leftrightarrow2A=2^{2009}+2^{2008}+.......+2\)
\(\Leftrightarrow2A-A=\left(2^{2010}+2^{2008}+.....+2\right)-\left(2^{2009}+2^{2008}+....+2+1\right)\)
\(\Leftrightarrow A=2^{2010}-1\)
\(\Leftrightarrow M=2^{2010}-\left(2^{2010}-1\right)\)
\(2^{2009}-\left(2^{2010}-\left(2^{2009}-2^{2008}\right)\right)=2^{2009}-2^{2010}+2^{2009}-2^{2008}\)
\(=2^{2008}\left(2-2^2+2-1\right)=-2^{2008}\)
A=2^2010+2^2009+2^2008+...+2^2+2
2A=2^2011+2^2010+2^2009+...+2^3+2^2
2A-A=(2^2011+2^2010+2^2009+...+2^3+2^2)-(2^2010+2^2009+2^2008+...+2^2+2)
A=2^2011-2.
A = 1 + 2 + 22 + 23 + ................................ + 22008 + 22009 + 22010
A = 1 + ( 2 + 22 + 23 + ................................ + 22008 + 22009 + 22010)
A = 1 + [(2 + 22 + 23) + (24 + 25 + 26) + ..................... + ( 22008 + 22009 + 22010)]
A = 1+ [2.(1 + 2 + 4) + 24.(1 + 2 + 4) + .......................+ 22008.(1 + 2 + 4)]
A = 1 + [2 . 7 + 24 . 7 + ......................... + 22008.7]
A = 1 + 7.[2 + 24 + ....................... + 22008]
Vì 7.[2 + 24 + ....................... + 22008] chia hết cho 7
1 không chia hết cho 7
=> A chia 7 dư 1
Dễ quá, thực hiện qui tắc bỏ dấu ngoặc được:
\(2009+2009^2+....+2009^{2009}-1-2009-...-2009^{2008}\)
\(=-1+\left(2009-2009\right)+\left(2009^2-2009^2\right)+...+\left(2009^{2008}-2009^{2008}\right)+2009^{2008}\)
\(=2009^{2008}-1\)
\(=\left(2009-1\right)\left(2009^{2007}+2009^{2008}+...+2009+1\right)\)
\(=2008\left(2009^{2007}+2009^{2008}+...+2009+1\right)\) chia hết cho 2008
=> ĐPCM
Chứng Minh Rằng: (2009+20092+20093+20094+...+20092009)-(1+2009+20092+20093+...+20092008) chia hết cho 2008.
Đặt A=2009+20092+20093+20094+...+20092009, B=1+2009+20092+20093+20094+...+20092008
Ta có:
+)A=2009+20092+20093+20094+...+20092009
2009A= 20092+20093+20094+...+20092010
2009A-A=(20092+20093+20094+...+20092010)-(2009+20092+20093+20094+...+20092009)
2008A=20092010- 2009
=> A=(20092010- 2009)/2008
=> A chia hết cho 2008.
B=1+2009+20092+20093+20094+...+20092008
2009B=2009+20092+20093+20094+...+20092010
2009B-B=(2009+20092+20093+20094+...+20092010)-(1+2009+20092+20093+20094+...+20092009)
2008B=20092010-1
=>B=(20092010-1)/2008
=>B chia hết cho 2008
=> A-B chia hết cho 2008.
=> ĐPCM
2A=2+2^2+....+2^51
A=2A-A=(2+2^2+...+2^51)-(1+2+2^2+...+2^50)=2^51-1
5B=5^2+5^3+.....+5^101
4B=5B-B=(5^2+5^3+....+5^101)-(5+5^2+...+5^100)=5^101-5
=> B=(5^101-5)/4
Tk mk nha