Tính giá trị của biểu thức:
\(x^{2013}-2014.x^{2012}+2014.x^{2011}-2010+2014.x-2014\) khi x= 2013
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
2012×2013+2011/2014×2013-2015=2012×2013+2011/(2012+2)×2013-2015=2012×2013+2011/2012×2013+2×2015=2012×2013+2011/2012×2013+4026-2015=2012×2013+2011/2012×2013+2011=1
$\frac{\frac{2010}{2011}}{\frac{2012}{2013}}+\frac{\frac{2011}{2012}}{\frac{2013}{2014}}+\frac{\frac{2012}{2013}}{\frac{2014}{2015}}$
$\frac{\frac{2010}{2011}}{\frac{2012}{2013}}+\frac{\frac{2011}{2012}}{\frac{2013}{2014}}+\frac{\frac{2012}{2013}}{\frac{2014}{2015}}$
$\frac{\frac{2010+2011+2012}{2011+2012+2013}}{\frac{2012+2013+2014}{2013+2014+2015}}$
$\frac{\frac{2010}{2011}+\frac{2011}{2012}+\frac{2012}{2013}}{\frac{2012+2013+2014}{2013+2014+2015}}$
$\frac{\frac{2010+2011+2012}{2011+2012+2013}}{\frac{2012}{2013}+\frac{2013}{2014}+\frac{2014}{2015}}$
\(A=\left|x-2011\right|+\left|x-2012\right|+\left|x-2013\right|+\left|x-2014\right|+\left|x-2015\right|\)
\(=\left(\left|x-2011\right|+\left|x-2015\right|\right)+\left(\left|x-2012\right|+\left|x-2014\right|\right)+\left|x-2013\right|\)
Đặt \(B=\left|x-2011\right|+\left|x-2015\right|\)
\(=\left|x-2011\right|+\left|2015-x\right|\ge\left|x-2011+2015-x\right|=4\left(1\right)\)
Dấu"=" xảy ra \(\Leftrightarrow\left(x-2011\right)\left(2015-x\right)\ge0\)
\(\Leftrightarrow\hept{\begin{cases}x-2011\ge0\\2015-x\ge0\end{cases}}\)hoặc \(\hept{\begin{cases}x-2011< 0\\2015-x< 0\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x\ge2011\\x\le2015\end{cases}}\)hoặc \(\hept{\begin{cases}x< 2011\\x>2015\end{cases}\left(loai\right)}\)
\(\Leftrightarrow2011\le x\le2015\)
Đặt \(C=\left|x-2012\right|+\left|x-2014\right|\)
\(=\left|x-2012\right|+\left|2014-x\right|\ge\left|x-2012+2014-x\right|=2\left(2\right)\)
Dấu"="xảy ra \(\Leftrightarrow\left(x-2012\right)\left(2014-x\right)\ge0\)
\(\Leftrightarrow\hept{\begin{cases}x-2012\ge0\\2014-x\ge0\end{cases}}\)hoặc \(\hept{\begin{cases}x-2012< 0\\2014-x< 0\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x\ge2012\\x\le2014\end{cases}}\)hoặc\(\hept{\begin{cases}x< 2012\\x>2014\end{cases}\left(loai\right)}\)
\(\Leftrightarrow2012\le x\le2014\)
Ta có: \(\left|x-2013\right|\ge0;\forall x\left(3\right)\)
Dấu"="Xảy ra \(\Leftrightarrow\left|x-2013\right|=0\)
\(\Leftrightarrow x=2013\)
Từ (1),(2) và (3) \(\Rightarrow B+C+\left|x-2013\right|\ge6\)
Hay \(A\ge6\)
Dấu"="xảy ra \(\Leftrightarrow\hept{\begin{cases}2011\le x\le2015\\2012\le x\le2014\\x=2013\end{cases}}\)\(\Leftrightarrow x=2013\)
Vậy \(A_{min}=6\Leftrightarrow x=2013\)
Bạn xem lại đề câu a) cho rõ lại
Câu b) Tại x=2013 thì B=x2013-(x+1)x2012+(x+1)x2011-(x+1)x2010+...-(x+1)x2+(x+1)x-1
= x2013-x2013-x2012+x2012+x2011-x2011-x2010+..-x3 - x2+x2+x-1
= x-1 = 2012
\(\frac{x+4}{2010}+\frac{x+3}{2011}=\frac{x+2}{2012}+\frac{x+1}{2013}\)
\(\Leftrightarrow\left(\frac{x+4}{2010}+1\right)+\left(\frac{x+3}{2011}+1\right)=\left(\frac{x+2}{2012}+1\right)+\left(\frac{x+1}{2013}+1\right)\)
\(\Leftrightarrow\frac{x+2014}{2010}+\frac{x+2014}{2011}=\frac{x+2014}{2012}+\frac{x+2014}{2013}\)
\(\Leftrightarrow\frac{x+2014}{2010}+\frac{x+2014}{2011}-\frac{x+2014}{2012}-\frac{x+2014}{2013}=0\)
\(\Leftrightarrow\left(x+2014\right)\left(\frac{1}{2010}+\frac{1}{2011}-\frac{1}{2012}-\frac{1}{2013}\right)=0\)
\(\Leftrightarrow x+2014=0\)
\(\Leftrightarrow x=-2014\)
V...
Ta có :
x = 2013 => x + 1 = 2014
x2013 - 2014.x2012 + 2014.x2011 - 2010 + 2014x - 2014
= x2013 - (x + 1).x2012 + (x + 1).x2011 - 2010 + (x + 1)x - 2014
= x2013 - x2013 - x2012 + x2012 + x2011 - 2010 + x2 + x - 2014
= x2011 + x2 - x - 4024
Làm thì thấy nó có vấn đề ?????
ta có : x = 2013
=> x + 1 = 2014
Thay 2014 = x + 1 vào biểu thức , sau đó phân phối , là ra