so sánh 2 PS \(\frac{2013}{2014}\)và \(\frac{2003}{2004}\)
Cho A = \(\frac{2000}{2001}+\frac{2001}{2002}+\frac{2002}{2003}+\frac{2003}{2004}+\frac{2005}{2006}+\frac{2006}{2007}+\frac{2007}{2008}+\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}+\frac{2011}{2012}+\frac{2012}{2013}+\frac{2013}{2014}+\frac{2014}{2015}+\frac{2015}{2016}\)
Hãy so sánh tổng các phân số trong A và so sánh với 15.
mỗi số hạng trong biểu thức A đều nhỏ hơn 1 mà có 15 số nên tổng A sẽ nhỏ hơn 15
ta thay tong tren <1+1+1+1+1+1+1+1+1+1+1+1+1+1+1
hay tong tren be hon 15
cho 2 phân số A=2013/2014 và B=2003/2004 so sánh a và b
\(\frac{x+1}{2014}+\frac{x+2}{2013}+\frac{x+3}{2012}+\frac{x+10}{2005}+\frac{x+11}{2004}+\frac{x+12}{2003}\)
Đề đúng phải là:
\(\frac{x+1}{2014}+\frac{x+2}{2013}+\frac{x+3}{2012}=\frac{x+10}{2005}+\frac{x+11}{2004}+\frac{x+12}{2003}\)
Cộng mỗi phân thức thêm 1, quy đồng rồi chuyển sang 1 vế ta được:
\(\frac{x+2015}{2014}+\frac{x+2015}{2013}+\frac{x+2015}{2012}-\frac{x+2015}{2005}-\frac{x+2015}{2004}-\frac{x+2015}{2003}=0\)
\(\Leftrightarrow\left(x+2015\right)\left(\frac{1}{2014}+\frac{1}{2013}+\frac{1}{2012}-\frac{1}{2005}-\frac{1}{2004}-\frac{1}{2003}\right)=0\)
Mà BT tích sau luôn nhỏ hơn 0
=> x+2015=0 => x = -2015
\(\frac{x+1}{2014}+\frac{x+2}{2013}+\frac{x+3}{2012}=\frac{x+10}{2005}+\frac{x+11}{2004}+\frac{x+12}{2003}\)( như này đúng không ? :)) )
<=> \(\left(\frac{x+1}{2014}+1\right)+\left(\frac{x+2}{2013}+1\right)+\left(\frac{x+3}{2012}+1\right)=\left(\frac{x+10}{2005}+1\right)+\left(\frac{x+11}{2004}+1\right)+\left(\frac{x+12}{2003}+1\right)\)
<=> \(\frac{x+1+2014}{2014}+\frac{x+2+2013}{2013}+\frac{x+3+2012}{2012}=\frac{x+10+2005}{2005}+\frac{x+11+2004}{2004}+\frac{x+12+2003}{2003}\)
<=> \(\frac{x+2015}{2014}+\frac{x+2015}{2013}+\frac{x+2015}{2012}=\frac{x+2015}{2005}+\frac{x+2015}{2004}+\frac{x+12}{2003}\)
<=> \(\frac{x+2015}{2014}+\frac{x+2015}{2013}+\frac{x+2015}{2012}-\frac{x+2015}{2005}-\frac{x+2015}{2004}-\frac{x+12}{2003}=0\)
<=> \(\left(x+2015\right)\left(\frac{1}{2014}+\frac{1}{2013}+\frac{1}{2012}-\frac{1}{2005}-\frac{1}{2004}-\frac{1}{2003}\right)=0\)
Vì \(\frac{1}{2014}+\frac{1}{2013}+\frac{1}{2012}-\frac{1}{2005}-\frac{1}{2004}-\frac{1}{2003}\ne0\)
=> x + 2015 = 0
=> x = -2015
so sánh A và B
A = \(\frac{2003}{2004}+\frac{2004}{2005}\)và B = \(\frac{2003+2004}{2004+2005}\)
\(B=\frac{2003+2004}{2004+2005}=\frac{2003}{2004+2005}+\frac{2004}{2004+2005}\)
Ta có: \(\frac{2003}{2004}>\frac{2003}{2004+2005}\)
\(\frac{2004}{2005}>\frac{2004}{2004+2005}\)
\(\frac{2003}{2004}+\frac{2004}{2005}>\frac{2003+2004}{2004+2005}\)
\(A>B\)
Vậy A>B
\(\text{ Bài giải}\)
\(A=\frac{2003}{2004}+\frac{2004}{2005}=0,999500998 + 0,999501247=1.99900225\)
\(B=\frac{2003+2004}{2004+2005}=\frac{4007}{4009}=0,999501122\)
\(\text{Vì : }1,99900224>0,999501122\text{ nên }A>B\)
\(\text{Vậy : }A>B\)
a) So sánh \(\frac{2013}{2015}\) và \(\frac{2014}{2016}\)
b) So sánh \(\frac{2013+2014}{2014+2015}\) và \(\frac{2013}{2014}+\frac{2014}{2015}\)
a)\(\frac{2013}{2015}< \frac{2014}{2016}\)
b)\(\frac{2013+2014}{2014+2015}< \frac{2013}{2014}+\frac{2014}{2015}\)
ta có tính chất \(\frac{a}{b}\)>1 suy ra \(\frac{a.m}{b.m}\).........
cho 2 phân số a = 2013/2014 và b =2003/2004
so sánh a và b ta có a .... b
dấu > , < ,= thích hơpj vào chỗ chấm
Ta có:
\(a=\frac{2013}{2014}=1-\frac{1}{2014}\)
\(b=\frac{2003}{2004}=1-\frac{1}{2004}\)
Vì \(\frac{1}{2014}< \frac{1}{2004}\Rightarrow1-\frac{1}{2014}>1-\frac{1}{2004}\)
Vậy \(a>b\)
so sánh
\(\frac{2013}{2014}+\frac{2014}{2015}và\frac{2013+2014}{2014+2015}\)
Ta có: \(\frac{2013}{2014}>\frac{2013}{2014+2015}\) (1)
\(\frac{2014}{2015}>\frac{2014}{2014+2015}\) (2)
ộng caác bất đẳng thứa (1) và (2) vào vế với vế:
\(\frac{2013}{2014}+\frac{2014}{2015}>\frac{2013+2014}{2014+2015}\Rightarrow A>B\)
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So sánh:
\(A=\frac{2003}{2004}+\frac{2005}{2006};B=\frac{2003+2004}{2004+2005}\)
so sanh 2 PS \(\frac{2014}{2013}\)và \(\frac{20032003}{20022002}\)
Ta có:
\(\frac{20032003}{20022002}=\frac{20032003:10001}{20022002:10001}=\frac{2003}{2002}\)
\(\frac{2014}{2013}=\frac{2014.182}{366366}=\frac{366548}{366366}\)
\(\frac{2003}{2002}=\frac{2003.182}{366366}=\frac{364546}{366366}\)
\(\Rightarrow\frac{2014}{2013}>\frac{2003}{2002}\)