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Bài 1 : làm tương tự với bài 2;3 nhé
Ta có : \(f\left(0\right)=c=2010;f\left(1\right)=a+b+c=2011\)
\(\Rightarrow f\left(1\right)=a+b=1\)
\(f\left(-1\right)=a-b+c=2012\Rightarrow f\left(-1\right)=a-b=2\)
\(\Rightarrow a+b=1;a-b=2\Rightarrow2a=3\Leftrightarrow a=\dfrac{3}{2};b=\dfrac{3}{2}-2=-\dfrac{1}{2}\)
Vậy \(f\left(-2\right)=4a-2b+c=\dfrac{4.3}{2}-2\left(-\dfrac{1}{2}\right)+2010=6+1+2010=2017\)
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Ta có \(B=\left(\frac{2010}{2}+1\right)+\left(\frac{2009}{3}+1\right)+...+\left(\frac{2}{2010}+1\right)+\left(\frac{1}{2011}+1\right)+1\)
\(B=\frac{2012}{2}+\frac{2012}{3}+...+\frac{2012}{2010}+\frac{2012}{2011}+\frac{2012}{2012}\)
\(B=2012.\left(\frac{1}{2}+\frac{1}{3}+...+\frac{1}{2010}+\frac{1}{2011}+\frac{1}{2012}\right)\)
B=2012.A
=>A/B=1/2012
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Ta có: x=2011 \(\Rightarrow\)x+1=2012
\(\Rightarrow A=x^{2011}-\left(x+1\right).x^{2010}\)\(+\left(x+1\right)x^{2009}\)\(-\left(x+1\right)x^{2008}+...\)\(-\left(x+1\right)x^2+\left(x+1\right)x-1\)
=\(x^{2011}\)\(-x^{2011}-x^{2010}+x^{2010}+x^{2009}-x^{2009}-\)...\(-x^2+x^2+x-1\)
= \(x-1=2011-1=2010\)
=
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ta có x=-(1+2+...+2011+2012) đặt y=1+2+...+22011+22012=>x=-y
ta có 2y=2+22+...+22012+22013
-y=1+2+...+22011+22012
y =22013-1=>x=-22013+1=>2010x=2010(-22013+1)
tích đúng cho mk nha bài này mất công lắm
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Ta có: A = 22012 - 22011 - 22010 - ... - 21 - 20
=> 2A = 22013 - 22012 - 22011 - ... - 22 - 2
=> 2A + A = (22013 - 22012 - 22011 - ... - 22 - 2) + (22012 - 22011 - 22010 - ... - 21 - 20)
=> 3A = 22013 - 20
=> 3A = 22013 - 1
=> A = \(\frac{2^{2013}-1}{3}\)
Ta có: A = 2 2012 - 2 2011 - 2 2010 - ... - 2 1 - 2 0
=> 2A = 2 2013 - 2 2012 - 2 2011 - ... - 2 2 - 2 => 2A + A = (2 2013 - 2 2012 - 2 2011 - ... - 2 2 - 2) + (2 2012 - 2 2011 - 2 2010 - ... - 2 1 - 2 0 )