ta có :
\(\frac{2008}{2009}< 1\)
\(\frac{2009}{2010}< 1\)
\(\frac{2010}{2011}< 1\)
\(\frac{2011}{2012}< 1\)
\(\Rightarrow\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}+\frac{2011}{2012}< 1+1+1+1\)
\(\Rightarrow\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}+\frac{2011}{2012}< 4\)
vậy ....................
2008/2009+2009/2010+2010/2011+2011/2008 4
=2008/2008=1 4
Vì 1<4 nên 2008/2009+2009/2010+2011/2008 < 4