cho mn hỏi câu tính nhanh này với nhé
\(\left(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2014}\right)x\left(1+1x2+1x2x3-9\right)\)
giúp mn nhé mn sắp phải nộp zùi
K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Những câu hỏi liên quan
5 tháng 8 2015
\(\left(1-\frac{1}{7}\right).\left(1-\frac{1}{8}\right).\left(1-\frac{1}{9}\right)......\left(1-\frac{1}{2011}\right)\)
\(=\frac{6}{7}.\frac{7}{8}.\frac{8}{9}.....\frac{2010}{2011}\)
\(=\frac{6.7.8.9.....2010}{7.8.9.10.....2011}\)
\(=\frac{6}{2011}\)
30 tháng 11 2014
$\frac{\frac{2010}{2011}}{\frac{2012}{2013}}+\frac{\frac{2011}{2012}}{\frac{2013}{2014}}+\frac{\frac{2012}{2013}}{\frac{2014}{2015}}$
$\frac{\frac{2010}{2011}}{\frac{2012}{2013}}+\frac{\frac{2011}{2012}}{\frac{2013}{2014}}+\frac{\frac{2012}{2013}}{\frac{2014}{2015}}$
$\frac{\frac{2010+2011+2012}{2011+2012+2013}}{\frac{2012+2013+2014}{2013+2014+2015}}$
$\frac{\frac{2010}{2011}+\frac{2011}{2012}+\frac{2012}{2013}}{\frac{2012+2013+2014}{2013+2014+2015}}$
$\frac{\frac{2010+2011+2012}{2011+2012+2013}}{\frac{2012}{2013}+\frac{2013}{2014}+\frac{2014}{2015}}$
AH
Akai Haruma
Giáo viên
7 tháng 5 2019
Lời giải:
Ta có:
\(\left(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2011}\right)(x-2013)>3x-6039\)
\(\Leftrightarrow \left(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2011}\right)(x-2013)-(3x-6039)>0\)
\(\Leftrightarrow \left(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2011}\right)(x-2013)-3(x-2013)>0\)
\(\Leftrightarrow (x-2013)\left(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2011}-3\right)>0\)
Ta thấy:
\(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2011}-3=1-\frac{1}{2012}+1-\frac{1}{2013}+1+\frac{2}{2011}-3\)
\(=\frac{1}{2011}-\frac{1}{2012}+\frac{1}{2011}-\frac{1}{2013}>0\)
Do đó, để \( (x-2013)\left(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2011}-3\right)>0\) thì \(x-2013>0\)
\(\Leftrightarrow x>2013\). Vì $x$ là số nguyên bé nhất nên $x=2014$
\(\left(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2014}\right)x0=0\)
#)Giải :
\(\left(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2014}\right)\times\left(1+1\times2+1\times2\times3-9\right)\)
\(=\left(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2014}\right)\times\left(1+2+6-9\right)\)
\(=\left(\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2014}\right)\times0\)
\(=0\)
#~Will~be~Pens~#