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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
Đặt \(A=2^{2009}+2^{2008}+2^{2007}+...+2+1\\ \Rightarrow2A=2^{2010}+2^{2009}+2^{2008}+...+2^2+2\\ \Rightarrow2A-A=\left(2^{2010}+2^{2009}+2^{2008}+...+2^2+2\right)-\left(2^{2009}+2^{2008}+2^{2007}+...+2+1\right)\\ \Rightarrow A=2^{2010}-1\)
\(\Rightarrow M=2^{2010}-2^{2010}+1=1\)
\(M=2^{2010}-2^{2009}-2^{2008}-...-2^1-2^0\)
\(-M=-\left(2^{2010}-2^{2009}-2^{2008}-...-2^1-2^0\right)\)
\(-M=2^{2010}+2^{2009}+2^{2008}+...+2^1+2^0\)
\(-2M=2.\left(2^{2010}+2^{2009}+2^{2008}+...+2^1+2^0\right)\)
\(-2M=2^{2011}+2^{2010}+2^{2009}+...+2^2+2^1\)
\(-M=2^{2011}+2^{2010}+...+2^2+2^1-\left(2^{2010}+2^{2009}+2^{2008}+...+2^1+2^0\right)\)
\(-M=2^{2011}-1=>M=-2^{2011}+1\)
Đặt \(A=2^{2009}+2^{2008}+...+2^1+2^0.\)
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 \(A=2^{2009}+2^{2008}+...+2^1+2^0\)
Ta có: \(2A=2^{2010}+2^{2008}+...+2^1\)
=> \(2AtrừA=\left(2^{2010}+2^{2008}+...+2^1\right)trừ\left(2^{2009}+2^{2008}+...+2^1+2^0\right)\)
=> \(A=2^{2010}trừ1\)
Thay vào ta có:
\(M=2^{2010}trừ2^{2010}trừ1\)
\(\Rightarrow M=âm1\)
Xin lỗi. Máy mình không có dấu trừ. Nên viết thành chữ.
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!
a: Đặt a/b=c/d=k
=>a=bk; c=dk
\(\left(\dfrac{a+b}{c+d}\right)^2=\left(\dfrac{bk+b}{dk+d}\right)^2=\dfrac{b^2}{d^2}\)
\(\dfrac{a^2+b^2}{c^2+d^2}=\dfrac{b^2k^2+b^2}{d^2k^2+d^2}=\dfrac{b^2}{d^2}\)
Do đó: \(\left(\dfrac{a+b}{c+d}\right)^2=\dfrac{a^2+b^2}{c^2+d^2}\)
b: \(\dfrac{ab}{cd}=\dfrac{bk\cdot b}{dk\cdot d}=\dfrac{b^2}{d^2}\)
\(\left(\dfrac{a-b}{c-d}\right)^2=\left(\dfrac{bk-b}{dk-d}\right)^2=\dfrac{b^2}{d^2}\)
Do đó: \(\dfrac{ab}{cd}=\left(\dfrac{a-b}{c-d}\right)^2\)
a)
\(2009-\left|x-2009\right|=x\)
\(\Rightarrow\left|x-2009\right|=-\left(x-2009\right)\)
\(\Rightarrow x-2009\le0\)
\(\Rightarrow x\le2009\)
Vậy \(x\le2009\)
b)
Vì \(\left(2x+1\right)^{2008}\ge0\forall x\)
\(\left(y-\dfrac{2}{5}\right)^{2008}\ge0\forall y\)
\(\left|x+y-z\right|\ge0\forall x,y,z\)
\(\Rightarrow\left(2x+1\right)^{2008}+\left(y-\dfrac{2}{5}\right)^{2008}+\left|x+y-z\right|\ge0\forall x,y,z\)
Mà theo đề bài :
\(\left(2x+1\right)^{2008}+\left(y-\dfrac{2}{5}\right)^{2008}+\left|x+y-z\right|=0\)
\(\Rightarrow\left(2x+1\right)^{2008}=0;\left(y-\dfrac{2}{5}\right)^{2008}=0;\left|x+y-z\right|=0\)
*) Với \(\left(2x+1\right)^{2008}=0\)
\(\Rightarrow2x+1=0\)
\(\Rightarrow2x=-1\)
\(\Rightarrow x=\dfrac{-1}{2}\)
*) Với \(\left(y-\dfrac{2}{5}\right)^{2008}=0\)
\(\Rightarrow y-\dfrac{2}{5}=0\)
\(\Rightarrow y=\dfrac{2}{5}\)
*) Với \(\left|x+y-z\right|=0\)
\(\Rightarrow x+y-z=0\)
\(\Rightarrow\dfrac{-1}{2}+\dfrac{2}{5}-z=0\)
\(\Rightarrow\dfrac{-1}{10}-z=0\)
\(\Rightarrow z=\dfrac{-1}{10}\)
Vậy \(x=\dfrac{-1}{2};y=\dfrac{2}{5};z=\dfrac{-1}{10}\)
a, 2009 - \(\left|x-2009\right|\) = x
=> \(\left|x-2009\right|\) = 2009 - x
=> \(\left[{}\begin{matrix}x-2009=2009-x\\x-2009=-2009-x\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}2x=4018\\2x=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=2009\\x=0\end{matrix}\right.\)
Vậy x \(\in\)n { 2009 ; 0 }
Đặt \(A=2^{2009}+2^{2008}+...+2+2^0\)
\(=1+2+...+2^{2008}+2^{2009}\)
\(\Rightarrow2A=2+2^2+...+2^{2010}\)
\(\Rightarrow2A-A=\left(2+2^2+...+2^{2010}\right)-\left(1+2+...+2^{2009}\right)\)
\(\Rightarrow A=2^{2010}-1\)
\(\Rightarrow M=2^{2010}-\left(2^{2010}-1\right)\)
\(=2^{2010}-2^{2010}+1=1\)
Vậy M = 1