So sánh: \(A=\frac{2009^{2017}+1}{2009^{2016}+1}\) và \(B=\frac{2009^{2018}-2}{2009^{2017}-2}\)
Cho \(a+b+c=\frac{1}{2017}\) và \(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}=2017\). Tính \(\left(a^{2009}+b^{2009}+c^{2009}\right)\left(\frac{1}{a^{2009}}+\frac{1}{b^{2009}}+\frac{1}{c^{2009}}\right)\)
1 : So sánh :
A = 2016/2017 + 2017/2018 và B = 2
A =2006/2007 + 2007/2008 +2008/2009 và B =3
19/18 và 2005/2004
A=2016/2017+2017/2018
Do 2016/2017<1,2017/2018<1=> A<2 Hay A<B
So sánh:
A=\(\frac{2009^{2009}+1}{2009^{2010}+1}\)và B=\(\frac{2009^{2010}-2}{2009^{2011}-2}\)
\(B=\frac{2009^{2010}-2}{2009^{2011}-2}< 1\)
\(\Rightarrow B=\frac{2009^{2010}-2}{2009^{2011}-2}< \frac{2009^{2010}-2+2011}{2009^{2011}-2+2011}=\frac{2009^{2010}+2009}{2009^{2011}+2009}\)\(=\frac{2009.\left(2009^{2009}+1\right)}{2009.\left(2009^{2010}+1\right)}=\frac{2009^{2009}+1}{2009^{2010}+1}\)
Suy ra : \(\frac{2009^{2010}-2}{2009^{2011}-2}< \frac{2009^{2009}+1}{2009^{2010}+1}\) hay \(B< A\)
Vậy \(A>B\)
A=\(\frac{2009^{2009}+1}{2009^{2010}+1}\)
B=\(\frac{2009^{2010}-2}{2009^{2011}-2}\)
so sánh A và B
\(B=\frac{18}{37}-\frac{8}{2017}+\frac{19}{37}-1\frac{2009}{2017}+\frac{2017}{2018}\)
\(B=\frac{18}{37}-\frac{8}{2017}+\frac{19}{37}-1\frac{2009}{2017}+\frac{2017}{2018}\)
\(B=\left(\frac{18}{37}+\frac{19}{37}\right)-\left(\frac{8}{2017}+1\frac{2009}{2017}\right)+\frac{2017}{2018}\)
\(B=1-\left(\frac{8}{2017}+\frac{4026}{2017}\right)+\frac{2017}{2018}\)
\(B=1-2+\frac{2017}{2018}\)
\(B=-1+\frac{2017}{2018}=\frac{-2018}{2018}+\frac{2017}{2018}\)
\(B=\frac{-1}{2018}\)
CHÚC BN HỌC TỐT!!!!!!
mk nha!!
AI GIÚP EM VỚI!....
so sánh
a) 2009/2010 và 2010/2011
b) 2008/2008.2009 và 2009/2009.2010
c) 2016/2017 +2017/2018 và 2016+2017/2016+2017
d) 1/3^400 và 1/4^300
kí hiệu : . = dấu nhân
^ = mũ
a, \(\dfrac{2009}{2010}\) và \(\dfrac{2010}{2011}\)
Ta có:
\(2009.2011=4040099\)
\(2010.2010=4040100\)
Vì \(2009.2011< 2010.2010\)
nên \(\dfrac{2009}{2010}< \dfrac{2010}{2011}\)
b, \(\dfrac{2008}{2008.2009}\) và \(\dfrac{2009}{2009.2010}\)
Ta có:
\(\dfrac{2008}{2008.2009}=\dfrac{1}{2009};\dfrac{2009}{2009.2010}=\dfrac{1}{2010}\)
Vì \(\dfrac{1}{2009}>\dfrac{1}{2010}\) nên \(\dfrac{2008}{2008.2009}>\dfrac{2009}{2009.2010}\)
Chúc bạn học tốt!!!
a)\(\dfrac{a}{b}< 1\Leftrightarrow\dfrac{a+m}{b+m}< 1\left(m\in N\right)\)
\(\dfrac{2009}{2010}< 1\)
\(\Leftrightarrow\dfrac{2009}{2010}< \dfrac{2009+1}{2010+1}\Leftrightarrow\dfrac{2009}{2010}< \dfrac{2010}{2011}\)
b)
\(\dfrac{2008}{2008.2009}=\dfrac{1}{2009}\)
\(\dfrac{2009}{2009.2010}=\dfrac{1}{2010}\)
\(\dfrac{1}{2009}>\dfrac{1}{2010}\Leftrightarrow\dfrac{2008}{2008.2009}>\dfrac{2009}{2009.2010}\)
d)
\(\dfrac{1}{3^{400}}=\dfrac{1}{\left(3^4\right)^{100}}=\dfrac{1}{81^{100}}\)
\(\dfrac{1}{4^{300}}=\dfrac{1}{\left(4^3\right)^{100}}=\dfrac{1}{64^{100}}\)
\(81^{100}>64^{100}\Leftrightarrow\dfrac{1}{81^{100}}< \dfrac{1}{64^{100}}\)
a, Lấy 1 trừ từng phân số.
\(1-\dfrac{2009}{2010}=\dfrac{1}{2010}\)
\(1-\dfrac{2010}{2011}=\dfrac{1}{2011}\)
Vì \(\dfrac{1}{2010}>\dfrac{1}{2011}\) nên \(\dfrac{2009}{2010}< \dfrac{2010}{2011}\).
b, \(\dfrac{2008}{2008.2009}=\dfrac{1}{2009}\)
\(\dfrac{2009}{2009.2010}=\dfrac{1}{2010}\)
Vì \(\dfrac{1}{2009}>\dfrac{1}{2010}\) nên \(\dfrac{2008}{2008.2009}>\dfrac{2009}{2009.2010}\)
c, Ta có:
\(\dfrac{2016}{2017}>\dfrac{2016}{2018}\Rightarrow\dfrac{2016}{2017}+\dfrac{2017}{2018}>\dfrac{2016}{2018}+\dfrac{2017}{2018}\)
\(\Rightarrow\dfrac{2016}{2017}+\dfrac{2017}{2018}>\dfrac{2016+2017}{2018}\)
\(\dfrac{2016+2017}{2017+2018}=\dfrac{2016+2017}{4035}\)
Vì \(\dfrac{2016+2017}{2018}>\dfrac{2016+2017}{4035}\) nên \(\dfrac{2016}{2017}+\dfrac{2017}{2018}>\dfrac{2016+2017}{2017+2018}\)
d, \(\left(\dfrac{1}{3}\right)^{400}=\left(\dfrac{1}{3}\right)^{4^{100}}=\left(\dfrac{1}{81}\right)^{100}\)
\(\left(\dfrac{1}{4}\right)^{300}=\left(\dfrac{1}{4}\right)^{3^{100}}=\left(\dfrac{1}{64}\right)^{100}\)
Vì \(\left(\dfrac{1}{81}\right)^{100}< \left(\dfrac{1}{64}\right)^{100}\) nên \(\left(\dfrac{1}{3}\right)^{400}< \left(\dfrac{1}{4}\right)^{300}\)
So sánh : \(A=\frac{2009^{2009}+1}{2009^{2010}+1}\)và \(B=\frac{2009^{2010}-2}{2009^{2011}-2}\)
Giải hẳn ra nhé
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
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
NO!!!!!!!!!!!!!!!!!!!!BÀI MÌNH SAI NHA
So sánh \(A=\frac{2009^{2009}+1}{2009^{2010}+1}\)và \(B=\frac{2009^{2010}-2}{2009^{2011}-2}\)
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
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
A=\(\frac{2009^{2009}+1}{2009^{2010+1}}\)và B=\(\frac{2009^{2010}-2}{2009^{2011}-2}\)
so sánh
nhân A 2009 lần và B 2009 lần mà so sánh
ta có:
B=(2009^2010-2)/(2009^2011-2)<1
=>(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
Vậy A=B
Đúng thì !
gộp số 2009 (số to to) ấythành 1 , sau đấy gộp số 1+1=2
sau đấy lấy 2009 chia cho hiệu của 2009-2010 +2
sau đó ta có 2009:-1+2
tính tông nó ra!!! Thế là hết bài
Bài giải đây nhé:
A= (20092009+1):(20092010+1) ( chia là phân số nhé)
A= (20092009):(20092010)+2
A= 2009:(2009-2010)+2
A= 2009:(-1)+2
A= (-2009)+2
A= -2007