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Tính:
\(A=2^{2012}-\left(2^{2011}+2^{2010}+...+2+1\right)\)
Giúp mk nốt bài này nha mọi ng. Mk cần 23h
Đặt \(B=2^{2011}+2^{2010}+\cdots+2+1\)
=>2B=\(2^{2012}+2^{2011}+\cdots+2^2+2\)
=>2B-B=\(2^{2012}+2^{2011}+\cdots+2^2+2-2^{2011}-2^{2010}-\cdots-2-1\)
=>\(B=2^{2012}-1\)
Ta có: \(A=2^{2012}-\left(2^{2011}+2^{2010}+\cdots+2+1\right)\)
\(=2^{2012}-\left(2^{2012}-1\right)\)
=1
f(0)=2010
=>\(a\cdot0^2+b\cdot0+c=2010\)
=>c=2010
=>\(f\left(x\right)=a\cdot x^2+bx+2010\)
\(f\left(1\right)=2011\)
=>\(a\cdot1^2+b\cdot1+2010=2011\)
=>a+b=1
f(-1)=2012
=>\(a\cdot\left(-1\right)^2+b\cdot\left(-1\right)+2010=2012\)
=>a-b=2
mà a+b=1
nên a=(2+1)/2=1,5; b=1-1,5=-0,5
=>f(x)=1,5x^2-0,5x+2010
\(f\left(-2\right)=1,5\cdot\left(-2\right)^2-0,5\cdot\left(-2\right)+2010\)
=6+1+2010
=2017
Ta có:
\(\frac{x+4}{2008}+1+\frac{x+3}{2009}+1=\frac{x+2}{2010}+1+\frac{x+1}{2011}+1\)
\(\frac{x+2012}{2008}+\frac{x+2012}{2009}=\frac{x+2012}{2010}+\frac{x+2012}{2011}\)
\(\left(x+2012\right)\left(\frac{1}{2008}+\frac{1}{2009}-\frac{1}{2010}-\frac{1}{2011}\right)=0\)
\(x=-2012\)
Ta có : \(\frac{x+1}{2013}+\frac{x+2}{2012}+\frac{x+3}{2011}=-3.\)
\(\Leftrightarrow\frac{x+1}{2013}+1+\frac{x+2}{2012}+1+\frac{x+3}{2011}+1=-3+3\)
\(\Leftrightarrow\frac{x+2014}{2013}+\frac{x+2014}{2012}+\frac{x+2014}{2011}=0\)
\(\Leftrightarrow\left(x+2014\right)\left(\frac{1}{2013}+\frac{1}{2012}+\frac{1}{2011}\right)=0\)
Mà \(\frac{1}{2013}+\frac{1}{2012}+\frac{1}{2011}\ne0\) nên \(x+2014=0\Leftrightarrow x=-2014\)
Vây \(x=-2014\)
hừm
=chịu
= 2,3323...