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L
30 tháng 5 2019
Bài giải
Theo bài ra :
\(A=\frac{2009}{2010}+\frac{2010}{2011}+\frac{2011}{2012}\)
\(B=\frac{2009+2010+2011}{2010+2011+2012}=\frac{2009}{2010+2011+2012}+\frac{2010}{2010+2011+2012}+\frac{2011}{2010+2011+2012}\)
Ta có :
\(\frac{2009}{2010}>\frac{2009}{2010+2011+2012}\)
\(\frac{2010}{2011}>\frac{2010}{2010+2011+2012}\)
\(\frac{2011}{2012}>\frac{2011}{2010+2011+2012}\)
\(\Rightarrow\text{ }\frac{2009}{2010}+\frac{2010}{2011}+\frac{2011}{2012}>\frac{2009}{2010+2011+2012}+\frac{2010}{2010+2011+2012}+\frac{2011}{2010+2011+2012}\)
\(\Rightarrow\text{ }A>B\)
HN
12 tháng 1 2019
\(B=\frac{2009^{2010}-2}{2009^{2011}-2}< 1\)
\(\Rightarrow B=\frac{2009^{2010}-2}{2009^{2011}-2}< \frac{2009^{2010}-2+2011}{2009^{2011}-2+2011}=\frac{2009^{2010}+2009}{2009^{2011}+2009}\)\(=\frac{2009.\left(2009^{2009}+1\right)}{2009.\left(2009^{2010}+1\right)}=\frac{2009^{2009}+1}{2009^{2010}+1}\)
Suy ra : \(\frac{2009^{2010}-2}{2009^{2011}-2}< \frac{2009^{2009}+1}{2009^{2010}+1}\) hay \(B< A\)
Vậy \(A>B\)
ND
0
10 tháng 6 2020
\(B=\frac{2008+2009+2010}{2009+2010+2011}\)
\(=\frac{2008}{2009+2010+2011}+\frac{2009}{2009+2010+2011}+\frac{2010}{2009+2010+2011}\)
\(< \frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}=A\)
DV
20 tháng 8 2017
2009A=2009^2010+2009/2009^2010+1 2009B=2009^2011-4018/2009^2011-2
2009A=1 + 2009/2009^2010+1 B=1 - 4016/2009^2011-2
mình viết tách ra cho khỏi nhầm
vì A>1 và B<1
nên A>B
VẬY A>B AND kết bạn nha
20 tháng 8 2017
A=2009^2009+1/2009^2010+1 B=2009^2010-2/2009^2011-2
A=(2009^2009+1).10/2009^2010+1 B=(2009^2010-2).10/2009^2011-2
A=2009^2010+10/2009^2010+1 B= 2009^2011-20/2009^2010-2
A=(2009^2010+1)+9/2009^2010+1 B=(2009^2011-2)-18/2009^2010-2
A=1 + 9/2009^2010+1 B=1+(-18/2009^2010-2)
Vì 9/2009^2010+1 > (-18/2009^2010-2)
=>1 + 9/2009^2010+1>1+(-18/2009^2010-2)
Hay 2009^2009+1/2009^2010+1 > 2009^2010-2/2009^2011-2
Vậy A>B
28 tháng 3 2016
B = 2009^2010 - 2 / 2009^2011 - 2 < 2009^2010 - 2 + 2011 /2009^2011 - 2 + 2011
= 2009^2010 + 2009 / 2009^2011 + 2009
= 2009 ( 2009^2009 + 1) / 2009(2009^2010 + 1)
= 2009^2009 + 1 / 2009^2010 + 1 = A
=> B < A
28 tháng 3 2016
B=20092010-2/20092011-2<20092010-2+2011/20092011-2+2011=20092010+2009/20092011+2009 =2009.(20092009+1)/2009.(20092010+1)=20092009+1/20092010+1
Suy ra A>B
26 tháng 2 2018
Ta có :
\(B=\frac{2008+2009+2010}{2009+2010+2011}=\frac{2008}{2009+2010+2011}+\frac{2009}{2009+2010+2011}+\frac{2010}{2009+2010+2011}\)
Vì :
\(\frac{2008}{2009}>\frac{2008}{2009+2010+2011}\)
\(\frac{2009}{2010}>\frac{2009}{2009+2010+2011}\)
\(\frac{2010}{2011}>\frac{2010}{2009+2010+2011}\)
Nên \(\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}>\frac{2008}{2009+2010+2011}+\frac{2009}{2009+2010+2011}+\frac{2010}{2009+2010+2011}\)
\(\Rightarrow\)\(A>B\)
Vậy \(A>B\)
26 tháng 2 2018
Ta có: \(B=\frac{2008+2009+2010}{2009+2010+2011}\)
\(=\frac{2008}{2009+2010+2011}+\frac{2009}{2009+2010+2011}+\frac{2010}{2009+2010+2011}\)
Vì \(\frac{2008}{2009}>\frac{2008}{2009+2010+2011}\)
\(\frac{2009}{2010}>\frac{2009}{2009+2010+2011}\)
\(\frac{2010}{2011}>\frac{2010}{2009+2010+2011}\)
nên \(\frac{2008}{2009}+\frac{2009}{2010}+\frac{2010}{2011}>\frac{2008+2009+2010}{2009+2010+2011}\)
hay A > B
Vậy A > B
7 tháng 7 2017
Do 2009\(^{2010}\)-2 < 2009\(^{2011}\)-2 \(\Rightarrow\)B<1
Theo đề bài ta có:
B= \(\frac{2009^{2010}-2}{2009^{2011}-2}\)< \(\frac{2009^{2010}-2+2011}{2009^{2011}-2+2011}\)= \(\frac{2009^{2010}+2009}{2009^{2011}+2009}\)= \(\frac{2009.\left(1+2009^{2009}\right)}{2009.\left(1+2009^{2010}\right)}\)= \(\frac{2009^{2009}+1}{2009^{2010}+1}\)= A \(\Rightarrow\)B<A
\(A=2009.2011\)
\(B=2010.2010\)
Xét A:
\(2009.2011=2009.\left(2010+1\right)=2009.2010+2009\)
Xét B:
\(2010.2010=2010.\left(2009+1\right)=2010.2009+2010\)
Mà \(2009.2010+2009< 2010.2009+2010\)\(\Rightarrow A< B\)
Vậy A < B
Ta có: \(A=2009.2011=2009\left(2010+1\right)=2009.2010+2009\)
\(B=2010^2=2010.2010=2010\left(2009+1\right)=2009.2010+2010\)
Vì \(2009< 2010\Rightarrow2009.2010+2009< 2009.2010+2010\Rightarrow A< B\)
Vậy A<B