So Sanh:
- A=2014^2013+1/2014^2012+1 B=2014^2013+1/2014^2011+1
- 10/a^m+10/a^n va 11/a^m+9/a^n (a,m,n thuoc N*)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(a^{2013}+b^{2013}=a^{2012}+b^{2012}\Rightarrow a^{2012}\left(a-1\right)+b^{2012}\left(b-1\right)=0\) (1)
\(a^{2014}+b^{2014}=a^{2013}+b^{2013}\Rightarrow a^{2013}\left(a-1\right)+b^{2013}\left(b-1\right)=0\) (2)
Trừ vế cho vế của (2) cho (1):
\(\left(a-1\right)\left(a^{2013}-a^{2012}\right)+\left(b-1\right)\left(b^{2013}-b^{2012}\right)=0\)
\(\Leftrightarrow a^{2012}\left(a-1\right)^2+b^{2012}\left(b-1\right)^2=0\)
\(\Rightarrow\left\{{}\begin{matrix}a^{2012}\left(a-1\right)^2=0\\b^{2012}\left(b-1\right)^2=0\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}a-1=0\\b-1=0\end{matrix}\right.\) \(\Rightarrow a=b=1\) (do \(a;b>0\))
\(\Rightarrow P=1+1=2\)
mình không biết kq =mấy
nhứng mình c/m kq =2 là sai
\(A-2=\dfrac{4024.2014-2}{Khongquantam}-2=\dfrac{4024.2014-2-2.2011-2.2012.2010}{Khongquantam}\)
\(A-2=\dfrac{2\left(2012.2014-2011-2012.2010-1\right)}{Khongquantam}=\dfrac{2\left[2012.\left(2014-2010\right)-2011-1\right]}{Khongquantam}\)
\(A-2=\dfrac{2\left[4.2012-2011-1\right]}{Khongquantam}=\dfrac{2\left[3.2011+3\right]}{Khongquantam}\)
\(A-2=\dfrac{2\left[3.\left(2011+1\right)\right]}{Khongquantam}=\dfrac{2.3.2012}{Khongquantam}\ne0\)\(A-2\ne0\)
\(\Rightarrow A\ne2\Rightarrow kq=2=sai\)
\(N=\frac{2012+2013+2014}{2013+2014+2015}=\frac{2012}{2013+2014+2015}+\frac{2013}{2013+2014+2015}+\frac{2014}{2013+2014+2015}\)
Ta thấy: \(\frac{2012}{2013}>\frac{2012}{2013+2014+2015}\)
\(\frac{2013}{2014}>\frac{2013}{2013+2014+2015}\)
\(\frac{2014}{2015}>\frac{2014}{2013+2014+2015}\)
\(\Rightarrow M=\frac{2012}{2013}+\frac{2013}{2014}+\frac{2014}{2015}>N=\frac{2012}{2013+2014+2015}+\frac{2013}{2013+2014+2015}+\frac{2014}{2013+2014+2015}\)
Vậy M>N