1-2013/2015=2/2015
1-2015/2017=2/2017
Vì 2/2015>2/2017=>2013/2015<2015/2017
Dùng cách so sánh phần bù nha bạn, như bạn Dũng đã làm
\(1-\frac{2013}{2015}=\frac{2}{2015}\)
\(1-\frac{2015}{2017}=\frac{2}{2017}\)
Vì \(\frac{2}{2015}>\frac{2}{2017}\Rightarrow\frac{2013}{2015}< \frac{2015}{2017}\)
Ta có :
\(1-\frac{2013}{2015}=\frac{2015-2013}{2015}=\frac{2}{2015}\)
\(1-\frac{2015}{2017}=\frac{2017-2015}{2017}=\frac{2}{2017}\)
Vì \(\frac{2}{2015}>\frac{2}{2017}\)
Nên \(\frac{2013}{2015}< \frac{2015}{2017}\)
\(\frac{2013}{2015}=\frac{2013}{2015}+\frac{2}{2015}=1\)
\(\frac{2015}{2017}=\frac{2015}{2017}+\frac{2}{2017}=1\)
=> Ta so sánh \(\frac{2}{2015}\)và \(\frac{2}{2017}\)
Ta thấy \(\frac{2}{2015}>\frac{2}{2017}\)
=> \(\frac{2013}{2015}>\frac{2015}{2017}\)
Ta có :
\(\frac{2013}{2015}=1-\frac{2}{2015}\)
\(\frac{2015}{2017}=1-\frac{2}{2017}\)
Vì \(\frac{2}{2015}>\frac{2}{2017}\)nên \(1-\frac{2}{2015}< 1-\frac{2}{2017}\)
Vậy \(\frac{2013}{2015}< \frac{2015}{2017}\)
