cho biểu thức A= 2013/2024+2014/2025+2015/2013.HÃY so sánh A với 3
Cho biểu thức A= 2013/2014 + 2014/2015 + 2015/2013. Hãy so sánh A với 3.( Mọi người giải đầy đủ giúp mình nhá! Cảm ơn!)
Cho biểu thức A = \(\frac{2013}{2014}+\frac{2014}{2015}+\frac{2015}{2013}\). Hãy so sánh A với 3.
\(A=\frac{2013}{2014}+\frac{2014}{2015}+\frac{2013}{2013}+\frac{1}{2013}+\frac{1}{2013}=\left(\frac{2013}{2014}+\frac{1}{2013}\right)+\left(\frac{2014}{2015}+\frac{1}{2013}\right)+1\)
Ta có: \(\frac{2013}{2014}+\frac{1}{2013}>\frac{2013}{2014}+\frac{1}{2014}=\frac{2014}{2014}=1\)
\(\frac{2014}{2015}+\frac{1}{2013}>\frac{2014}{2015}+\frac{1}{2015}=\frac{2015}{2015}=1\)
=> A > 1+ 1 + 1 = 3
So sánh các biểu thức sau: A =2013+2014/2014+2015 và B=2013/2014 + 2014/2015
A=\(\dfrac{2013+2014}{2014+2015}=\dfrac{2013}{2014+2015}+\dfrac{2014}{2014+2015}\)
B=\(\dfrac{2013}{2014}+\dfrac{2014}{2015}\)
Vì \(\dfrac{2013}{2014}>\dfrac{2013}{2014+2015}\); \(\dfrac{2014}{2015}>\dfrac{2014}{2014+2015}\) nên B>A
cho biểu thức A=2013 /2014+2014/2015+2015/2016 SO SÁNH A vs 3
Ta có :
\(\frac{2013}{2014}< 1\)( 1 )
\(\frac{2014}{2015}< 1\)( 2 )
\(\frac{2015}{2016}< 1\)( 3 )
từ ( 1 ) , ( 2 ) và ( 3 )
\(\Rightarrow\frac{2013}{2014}+\frac{2014}{2015}+\frac{2015}{2016}< 1+1+1=3\)
vậy A < 3
Có: 2013/2014<2014/2014
2014/2015<2015/2015
2015/2016<2016/2016
=>2013/2014+2014/2015+2015/2016<2014/2014+2015/015+2016/2016
=>A<3
Có: 2013/2014<2014/2014
2014/2015<2015/2015
2015/2016<2016/2016
=>2013/2014+2014/2015+2015/2016<2014/2014+2015/015+2016/2016
=>A<3
Cho : A = 2013/2014 + 2014/2015 + 2015/2013
Hãy so sánh A với 3
A= 2013/2014 + 2014/2015 + 2015/2013. So sánh A với 3
Cho phép tính : A = 2013/2014 + 2014/2015 + 2015/2013
Hãy tính xem A bằng bao nhiêu và so sánh A với 3
\(\frac{2013}{2014}+\frac{2014}{2015}+\frac{2015}{2013}\)
= \(\frac{2013}{2014}+\frac{2014}{2015}+\frac{2013}{2013}+\frac{1}{2013}+\frac{1}{2013}\)
= \(\left(\frac{2013}{2014}+\frac{1}{2013}\right)+\left(\frac{2014}{2015}+\frac{1}{2013}\right)+1\)
Ta có :\(\frac{2013}{2014}+\frac{1}{2013}>\frac{2013}{2014}+\frac{1}{2014}=1\)
\(\frac{2014}{2015}+\frac{1}{2013}>\frac{2014}{2015}+\frac{1}{2015}=1\)
=> A > 1 + 1 + 1 = 3
Vậy A > 3
cho B = 2012/2013 + 2013/2014 + 2015/2012 . hãy so sánh B với 3
\(B=\frac{2013-1}{2013}+\frac{2014-1}{2014}+\frac{2012+3}{2012}\)
\(B=1-\frac{1}{2013}+1-\frac{1}{2014}+1+\frac{3}{2012}=3+\frac{3}{2012}-\left(\frac{1}{2013}+\frac{1}{2014}\right)\)
Ta có
\(\frac{1}{2013}< \frac{1}{2012};\frac{1}{2014}< \frac{1}{2012}\Rightarrow\frac{1}{2013}+\frac{1}{2014}< \frac{2}{2012}\)
Mà \(\frac{3}{2012}-\frac{2}{2012}=\frac{1}{2012}>0\Rightarrow\frac{3}{2012}-\left(\frac{1}{2013}+\frac{1}{2014}\right)>0\)
=> B>3
cho B = 2012/2013 + 2013/2014 + 2015/2012 . hãy so sánh B với 3
\(B=\frac{2012}{2013}+\frac{2013}{2014}+\frac{2015}{2012}\)
\(B=\frac{2012}{2013}+\frac{2013}{2014}+\left(\frac{1}{2012}+\frac{1}{2012}+\frac{2013}{2012}\right)\)
\(B=\left(\frac{2012}{2013}+\frac{1}{2012}\right)+\left(\frac{2013}{2014}+\frac{1}{2012}\right)+\frac{2013}{2012}\)
\(3=1+1+1\)
\(\frac{2012}{2013}+\frac{1}{2012}>1\)
\(\frac{2013}{2014}+\frac{1}{2012}>1\)
\(\frac{2013}{2012}>1\)
vậy B > 3