Vậy có ai biết làm ko giúp tớ nhé !
4) So sánh A=2005^2005+1/2005^2006+1 và B=2005^2004+1/ 2003^2009+2
Giúp mình nha!
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(A=\frac{2003\cdot2004-1}{2003\cdot2004}=1-\frac{1}{2003\cdot2004}\)
\(B=\frac{2004\cdot2005-1}{2004\cdot2005}=1-\frac{1}{2004\cdot2005}\)
Vì 1 = 1 và \(\frac{1}{2003\cdot2004}>\frac{1}{2004\cdot2005}\) nên A > B
Vậy A > B
Chắc sai =))
\(A=\frac{2003\cdot2004-1}{2003\cdot2004}=\frac{2003\cdot2004}{2003\cdot2004}-\frac{1}{2003\cdot2004}=1-\frac{1}{2003\cdot2004}\)
\(B=\frac{2004\cdot2005-1}{2004\cdot2005}=\frac{2004\cdot2005}{2004\cdot2005}-\frac{1}{2004\cdot2005}=1-\frac{1}{2004\cdot2005}\)
có : \(\frac{1}{2003\cdot2004}>\frac{1}{2004\cdot2005}\)
\(\Rightarrow1-\frac{1}{2003\cdot2004}< 1-\frac{1}{2004\cdot2005}\)
\(\Rightarrow A< B\)
a)2012/2013<2013/2014
b)2003x........< 2007x......
cho mình nha
Ta có : A=2005^2005+1/2005^2006+1
=>2005A=2005.(2005^2005+1)/2005^2006+1
=>2005A=2005^2006+2005/2005^2006+1
=>2005A=2005^2006+1+2004/2005^2006+1
=>2005A=2005^2006+1/2005^2006+1 + 1/2005^2006+1
=>2005A=1+1/2005^2006+1
Lại có:B=2005^2004+1/2005^2005+1
=>2005B=2005.(2005^2004+1)/2005^2005+1
=>2005B=2005^2005+2005/2005^2005+1
=>2005B=2005^2005+1+2004/2005^2005+1
=>2005B=2005^2005+1/2005^2005+1 + 1/2005^2005+1
=>2005B=1+1/2005^2005+1
Vì 2006>2005
=>2005^2006>2005^2005
=>2005^2006+1>2005^2005+1
=>1/2005^2006+1<1/2005^2005+1
=>1+1/2005^2006+1<1+1/2005^2005+1
=>2005A<2005B
=>A<B
Vậy A<B
Ủng hộ mik nha mọi người !!!
\(10A=\frac{2005^{2006}+10}{2005^{2006}+1}\)
\(10B=\frac{2005^{2005}+10}{2005^{2005}+1}\)
Rồi bạn so sánh 10A và 10B là ra.
Ai thấy đúng thì ủng hộ nha !!!, sai thì góp ý cho mink nha
Ta có
A <\(\frac{2005^{2005}+2005}{2005^{2006}+2005}=\frac{2005\left(2005^{2004}+1\right)}{2005\left(2005^{2005}+1\right)}\)=\(\frac{2005^{2004}+1}{2005^{2005}+1}\)
\(\RightarrowĐPCM\)
\(2005A=\frac{2005\left(2005^{2005}+1\right)}{2005^{2006}+1}=\frac{2005^{2006}+2005}{2005^{2006}+1}=\frac{2005^{2006}+1+2004}{2005^{2006}+1}=\frac{2005^{2006}+1}{2005^{2006}+1}+\frac{2004}{2005^{2006}+1}=1+\frac{2004}{2005^{2006}+1}\)
\(2005B=\frac{2005\left(2005^{2004}+1\right)}{2005^{2005}+1}=\frac{2005^{2005}+2005}{2005^{2005}+1}=\frac{2005^{2005}+1+2004}{2005^{2005}+1}=\frac{2005^{2005}+1}{2005^{2005}+1}+\frac{2004}{2005^{2005}+1}=1+\frac{2004}{2005^{2005}+1}\)
vì 20052006+1>20052005+1
\(\Rightarrow\frac{4}{2005^{2006}+1}< \frac{4}{2005^{2005}+1}\)
\(\Rightarrow1+\frac{4}{2005^{2006}+1}< 1+\frac{4}{2005^{2005}+1}\)
=>A<B
A=20052005+120052006+1<20052005+1+200420052006+1+2004=2005.(20052004+1)2005.(20052005+1)==20052004+120052005+1=B.�=20052005+120052006+1<20052005+1+200420052006+1+2004=2005.(20052004+1)2005.(20052005+1)==20052004+120052005+1=�.
Vậy A < B
A=20052005+120052006+1<20052005+1+200420052006+1+2004=2005.(20052004+1)2005.(20052005+1)==20052004+120052005+1=B.�=20052005+120052006+1<20052005+1+200420052006+1+2004=2005.(20052004+1)2005.(20052005+1)==20052004+120052005+1=�.
Vậy A < B