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2005/2006=1-1/2006
2006/2007=1-1/2007
mà 1/2006>1/2008
->1-1/2006<1-1/2007
hay 2005/2006<2006/2007
k mk nha
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Ta có: \(1-\frac{2005}{2006}=\frac{2006-2005}{2006}=\frac{1}{2006}\)
\(1-\frac{2006}{2007}=\frac{2007-2006}{2007}=\frac{1}{2017}\)
Vì \(\frac{1}{2006}>\frac{1}{2007}\)
\(\Rightarrow\frac{2005}{2006}< \frac{2006}{2007}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có: \(A=\dfrac{2005}{2006}+\dfrac{2006}{2007}+\dfrac{2007}{2005}=\dfrac{2006-1}{2006}+\dfrac{2007-1}{2007}+\dfrac{2005}{2005}+\dfrac{1}{2005}+\dfrac{1}{2005}\)\(=1+1+1+\left(\dfrac{1}{2005}-\dfrac{1}{2006}+\dfrac{1}{2005}-\dfrac{1}{2007}\right)\)
\(=3+\left(\dfrac{1}{2005}-\dfrac{1}{2006}+\dfrac{1}{2005}-\dfrac{1}{2007}\right)\)
Ta thấy: \(\dfrac{1}{2005}>\dfrac{1}{2006};\dfrac{1}{2005}>\dfrac{1}{2007}\) \(\Rightarrow\dfrac{1}{2005}-\dfrac{1}{2006}+\dfrac{1}{2005}-\dfrac{1}{2007}>0\)
\(\Rightarrow A>3\)
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Ta có: 1 - 2005/2006 = 1/2006
1 - 2006/2007 = 1/2007
Vì 1/2006 > 1/2007 nên 2005/2006 < 2006/2007
(trong hai phân số, phân số nào có phần bù lớn hơn thì phân số đó lớn hơn)
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a) Ta có:
\(1-\frac{2005}{2006}=\frac{1}{2006}\)
\(1-\frac{2006}{2007}=\frac{1}{2007}\)
Vì \(\frac{1}{2006}>\frac{1}{2007}\)nên \(\frac{2005}{2006}>\frac{2006}{2007}\)
b) Ta có:
\(\frac{2008}{2007}-1=\frac{1}{2007}\)
\(\frac{2007}{2006}-1=\frac{1}{2006}\)
Vì \(\frac{1}{2006}>\frac{1}{2007}\)nên \(\frac{2008}{2007}< \frac{2007}{2006}\)
a, \(\frac{2005}{2006}v\text{à}\frac{2006}{2007}\)= \(\frac{2005\cdot2007}{2006\cdot2007}\)và \(\frac{2006\cdot2006}{2007\cdot2006}\)
= \(\frac{4024035}{4026042}\)< \(\frac{4024036}{4026042}\)
b, \(\frac{2008}{2007}v\text{à}\frac{2007}{2006}\)= \(\frac{2008\cdot2006}{2007\cdot2006}v\text{à}\frac{2007\cdot2007}{2006\cdot2007}\)
=\(\frac{4028048}{4026042}\)< \(\frac{4028049}{4026042}\)