Question

[Lê Hoàng Tiến Đạt]

so sánh \(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2011}\) với 3

Answer 1

[tth_new]

Bài nãy sai rồi, cho mình làm lại nha:

\(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2011}=\frac{2012-1}{2012}+\frac{2013-1}{2013}+\frac{2011+1+1}{2011}\)

\(=1-\frac{1}{2012}+1-\frac{1}{2013}+1+\frac{1}{2011}\)

Vì: \(\frac{1}{2011}>\frac{1}{2012}>\frac{1}{2013}\Rightarrow\frac{1}{2011}+\frac{1}{2012}-\frac{1}{2012}+\frac{1}{2012}>0\)

\(\Rightarrow\frac{2012-1}{2012}+\frac{2013-1}{2013}+\frac{2011+1+1}{2011}>3\)

Nên \(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2011}>3\)

Answer 2

[Lê Thị Khánh Huyền]

chịu........