So sánh:
A = \(\frac{2012^{2013}+2}{2012^{2013}-1}\)
B=\(\frac{2012^{2013}}{2012^{2013}-3}\)
So sánh:
A = \(\frac{2012^{2013}+2}{2012^{2013}-1}\)
B=\(\frac{2012^{2013}}{2012^{2013}-3}\)
So sánh phân thức A=\(\frac{2013^2-2012^2}{2013^2+2012^2}\) với B=\(\frac{2013-2012}{2013+2012}\)
So sánh \(\left(\frac{2012^{2012}}{2013^{2012}}+1\right)^{2013}\) và \(\left(\frac{2012^{2013}}{2013^{2013}}+1\right)^{2012}\)
Ta có \(\frac{2012^{2013}}{2013^{2013}}=\frac{2012^{2012}}{2013^{2012}}.\frac{2012}{2013}\)
Vì \(\frac{2012}{2013}< 1\)nên\(\frac{2012^{2012}}{2013^{2012}}.\frac{2012}{2013}< \frac{2012^{2012}}{2013^{2012}}.1=\frac{2012^{2012}}{2013^{2012}}\)
hay \(\frac{2012^{2013}}{2013^{2013}}< \frac{2012^{2012}}{2013^{2012}}\)
\(\Rightarrow\frac{2012^{2013}}{2013^{2013}}+1< \frac{2012^{2012}}{2013^{2012}}+1\)
\(\Rightarrow\left(\frac{2012^{2013}}{2013^{2013}}+1\right)^{2012}< \left(\frac{2012^{2012}}{2013^{2012}}+1\right)^{2013}\)
\(\)M=\(\frac{2012^{2012}}{2013^{2013}}\)và N=\(\frac{2012^{2012}+2012}{2013^{2013}+2013}\). So sánh M và N
\(M=\frac{2012}{2013}.\frac{2012^{2011}}{2013^{2011}}\)
\(N=\frac{2012}{2013}.\frac{2012^{2011}+1}{2013^{2011}+1}\)
Bạn tự so sánh tiếp nhé!
Đặt 20122012 = x ; 20132013 = y
Giả sử M < N
Ta có : \(\frac{x}{y}< \frac{x+2012}{y+2013}\)
\(\Leftrightarrow x\left(y+2013\right)< y\left(x+2012\right)\)
\(\Leftrightarrow xy+2013x< xy+2012y\)
\(\Leftrightarrow2013x< 2012y\)
\(\Leftrightarrow2013.2012^{2012}< 2012.2013^{2013}\)
\(\Leftrightarrow2012^{2011}< 2013^{2012}\)( Đúng )
=> Điều giả sử trên là đúng
=> M < N
Không tính cụ thể , hãy sắp xếp các biểu thức sau theo thứ tự giảm dần :
\(\frac{\frac{2010}{2011}}{\frac{2012}{2013}}+\frac{\frac{2011}{2012}}{\frac{2013}{2014}}+\frac{\frac{2012}{2013}}{\frac{2014}{2015}}\)
\(\frac{\frac{2010}{2011}+\frac{2011}{2012}+\frac{2012}{2013}}{\frac{2012}{2013}+\frac{2013}{2014}+\frac{2014}{2015}}\)
\(\frac{\frac{2010+2011+2012}{2011+2012+2013}}{\frac{2012+2013+2014}{2013+2014+2015}}\)
\(\frac{\frac{2010}{2011}+\frac{2011}{2012}+\frac{2012}{2013}}{\frac{2012+2013+2014}{2013+2014+2015}}\)
\(\frac{\frac{2010+2011+2012}{2011+2012+2013}}{\frac{2012}{2013}+\frac{2013}{2014}+\frac{2014}{2015}}\)
$\frac{\frac{2010}{2011}}{\frac{2012}{2013}}+\frac{\frac{2011}{2012}}{\frac{2013}{2014}}+\frac{\frac{2012}{2013}}{\frac{2014}{2015}}$
$\frac{\frac{2010}{2011}}{\frac{2012}{2013}}+\frac{\frac{2011}{2012}}{\frac{2013}{2014}}+\frac{\frac{2012}{2013}}{\frac{2014}{2015}}$
$\frac{\frac{2010+2011+2012}{2011+2012+2013}}{\frac{2012+2013+2014}{2013+2014+2015}}$
$\frac{\frac{2010}{2011}+\frac{2011}{2012}+\frac{2012}{2013}}{\frac{2012+2013+2014}{2013+2014+2015}}$
$\frac{\frac{2010+2011+2012}{2011+2012+2013}}{\frac{2012}{2013}+\frac{2013}{2014}+\frac{2014}{2015}}$
so sanh \(y=\frac{2012^{2012}}{2013^{2013}}\) va \(z=\frac{2012^{2012}+2012}{2013^{2013}+2013}\)
So sánh 2 số sau: M=\(\frac{2013^{2012}+2012}{2013^{2011}+1}\)và \(N=\frac{2013^{2011}+2012}{2013^{2010}+1}\)
Ta có :
\(\frac{1}{2013}M=\frac{2013^{2012}+2012}{2013^{2012}+2013}=\frac{2013^{2012}+2013}{2013^{2012}+2013}-\frac{1}{2013^{2012}+2013}=1-\frac{1}{2013^{2012}+2013}\)
Lại có :
\(\frac{1}{2013}N=\frac{2013^{2011}+2012}{2013^{2011}+2013}=\frac{2013^{2011}+2013}{2013^{2011}+2013}-\frac{1}{2013^{2011}+2013}=1-\frac{1}{2013^{2011}+2013}\)
Vì \(\frac{1}{2013^{2012}+2013}< \frac{1}{2013^{2011}+2013}\) nên \(M=1-\frac{1}{2013^{2012}}>N=1-\frac{1}{2013^{2011}+2013}\)
Vậy \(M>N\)
Chúc bạn học tốt ~
cho \(A=\frac{2011}{2012}+\frac{2012}{2013};B=\frac{2011+2013}{2012+2013}\)So sánh A và B
Gọi 2011 là a
2012 là b;2013 là c
=>\(A=\frac{2011}{2012}+\frac{2012}{2013}=\frac{a}{b}+\frac{b}{c}\);\(B=\frac{2011+2013}{2012+2013}=\frac{a+c}{b+c}\)
=>\(A=\frac{a}{b}+\frac{b}{c}=\frac{ac+b^2}{bc}\)\(=\frac{\left(ac+b^2\right).\left(b+c\right)}{bc.\left(b+c\right)}\);\(B=\frac{a+c}{b+c}=\frac{\left(a+c\right).bc}{bc.\left(b+c\right)}\)
b+c>a+c;b2+ac>bc
Vậy A>B
So sánh:
A=\(\frac{2013^{2012}-1}{2013^{2013}-1}\)và B=\(\frac{2013^{2011}+1}{2013^{2012}+1}\)