Tính nhanh hoặc tính hợp lí:
\(T=2^{2010}-\left(2^{2009}+2^{2008}+...+2^1+2^0\right)\)
Giúp mik gấp nha
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Đặt \(A=2^{2009}+2^{2008}+...+2^1+2^0\)
Ta có : \(2A=2^{2010}+2^{2009}+...+2^2+2^1\)
\(\Rightarrow2A-A=2^{2010}-2^0\Rightarrow A=2^{2010}-1\)
Do đó : \(M=2^{2010}-A=2^{2010}-\left[2^{2010}-1\right]=1\)
\(M=2^{2010}-\left(2^{2009}+2^{2008}+...+2^1+2^0\right)\)
\(2^{2010}-M=2^{2009}+2^{2008}+...+2+1\)
\(2\left(2^{2010}-M\right)=2\left(2^{2009}+2^{2008}+...+2+1\right)\)
\(2\left(2^{2010}-M\right)=2^{2010}+2^{2009}+...+2^2+2\)
\(2\left(2^{2010}-M\right)-M=\left(2^{2010}+2^{2009}+...+4+2\right)-\left(2^{2009}+2^{2008}+...+2+1\right)\)
\(2^{2010}-M=2^{2010}+2^{2009}+...+4+2-2^{2009}-2^{2008}-...-2-1\)
\(2^{2010}-M=2^{2010}-1\)
=> M = 1
1+2-3-4+5+6-7-8+...-2007-2008+2009+2010
= 1+(2-3)+(-4+5)+(6-7)+(-8+9)+........+(2006-2007)+(-2008+2009)+2010
=1+(-1)+1+(-1)+1+......+(-1)+1+(-1)+1+2010
=1+2010
=2011
\(M=2^{2010}-2^{2009}-2^{2008}-...-2^1-2^0\)
\(-M=-\left(2^{2010}-2^{2009}-2^{2008}-...-2^1-2^0\right)\)
\(-M=2^{2010}+2^{2009}+2^{2008}+...+2^1+2^0\)
\(-2M=2.\left(2^{2010}+2^{2009}+2^{2008}+...+2^1+2^0\right)\)
\(-2M=2^{2011}+2^{2010}+2^{2009}+...+2^2+2^1\)
\(-M=2^{2011}+2^{2010}+...+2^2+2^1-\left(2^{2010}+2^{2009}+2^{2008}+...+2^1+2^0\right)\)
\(-M=2^{2011}-1=>M=-2^{2011}+1\)
Đặt A=\(\left(2^{2009}+2^{2008}+...+2^1+2^0\right)\)
=> 2A=\(2^{2010}+2^{2009}+2^{2008}+...+2^2+2\)
=>2A-A=\(\left(2^{2010}+2^{2009}+2^{2008}+...+2^2+2\right)-\left(2^{2009}+2^{2008}+...+2^1+2^0\right)\)
=> A=22010-20
=>M=22010-A=22010-22010+20=1
đúng nhé!
a/\(\frac{\left(2^3.5.7\right).\left(5^2.7^3\right)}{\left(2.5.7^2\right)^2}\)
=\(\frac{2^3.5^3.7^4}{2^2.5^2.7^4}\)
=2.5
=10
Đặt \(A=2^{2009}+2^{2008}+...+2^1+2^0.\)
Ta có : \(2A=2^{2010}+2^{2009}+...+2^2+2^1.\)
Suy ra : \(2A-A=2^{2010}-2^0\Rightarrow A=2^{2010}-1.\)
Do đó \(M=2^{2010}-A=2^{2010}-\left(2^{2010}-1\right)=1.\)
Đặt A=22009+22008+...+21+20.A=22009+22008+...+21+20.
Ta có : 2A=22010+22009+...+22+21.2A=22010+22009+...+22+21.
Suy ra : 2A−A=22010−20⇒A=22010−1.2A−A=22010−20⇒A=22010−1.
Do đó M=22010−A=22010−(22010−1)=1.
Đặt \(A=2^{2009}+2^{2008}+2^{2007}+...+2+1\\ \Rightarrow2A=2^{2010}+2^{2009}+2^{2008}+...+2^2+2\\ \Rightarrow2A-A=\left(2^{2010}+2^{2009}+2^{2008}+...+2^2+2\right)-\left(2^{2009}+2^{2008}+2^{2007}+...+2+1\right)\\ \Rightarrow A=2^{2010}-1\)
\(\Rightarrow M=2^{2010}-2^{2010}+1=1\)
1.
M = 22010 - ( 22009 + 22008 + ... + 21 + 20 )
đặt N = 22009 + 22008 + ... + 21 + 20
2N = 22010 + 22009 + ... + 22 + 21
2N - N = ( 22010 + 22009 + ... + 22 + 21 ) - ( 22009 + 22008 + ... + 21 + 20 )
N = 22010 - 20
Thay N vào ta được :
M = 22010 - ( 22010 - 20 )
M = 22010 - 22010 + 20
M = 20 = 1
2.
Ta có :
2332 < 2333 = ( 23 ) 111 = 8111
3223 > 3222 = ( 32 ) 111 = 9111
Vì 2332 < 8111 < 9111 < 3223
đặt :
\(A=2^{2009}+2^{2008}+2^{2007}+...+2^1+2^0\\ 2A=2^{2010}+2^{2009}+...+2^2+2^1\\ 2A-A=\left(2^{2010}+2^{2009}+...+2^2+2^1\right)-\left(2^{2009}+2^{2008}+...+2^1+2^0\right)\\ A=2^{2010}-1\)
\(T=2^{2010}-A\\ T=2^{2010}-2^{2010}+1=1\)
T=22010 - (1 + 2+ ... + 22008 +22009)
Đặt A =(1 + 2+ ... + 22008 +22009)
2A=(2+22+...+22009+22010)
2A-A=(2+22+...+22009+22010)-(1 + 2+ ... + 22008 +22009)
A=22010-1
=> T=22010-(22010-1)
T=22010-22010+1
T=0+1
T=1
Vậy, ...
tick nha!