so sanh: A=2005^2005+1/2005^2006+1va B=2005^2004+1/2005^2005+1
A=20052005+1/20052006+1 : B=20052004+1/20052005+1
so sanh A va B
SO SÁNH A= 2005^2005+1/2005^2006+1 va B = 2005^2004+1/2005^2005+1
So sánh A và B :
a, A = 2006^2006 + 1 / 2006^2007 + 1 và B = 2006^2007 + 1 / 2006^2008 + 1
b, A = 2004 . 2005 - 1 / 2004 . 2005 và B = 2005 . 2006 - 1 / 2005 . 2006
SO SÁNH: 2005^2005+1/2005^2006+1 và B= 2005^2004+1/2005^2005+1
\(A=\frac{2005^{2005}+1}{2005^{2006}+1}\)
\(2005A=\frac{2005^{2006}+2005}{2005^{2006}+1}=\frac{2005^{2006}+1+2004}{2005^{2006}+1}=\frac{2005^{2006}+1}{2005^{2006}+1}+\frac{2004}{2005^{2006}+1}\)
\(B=\frac{2005^{2004}+1}{2005^{2005}+1}\)
\(2005B=\frac{2005^{2005}+2005}{2005^{2005}+1}=\frac{2005^{2005}+1+2004}{2005^{2005}+1}=\frac{2005^{2005}+1}{2005^{2005}+1}+\frac{2004}{2005^{2005}+1}\)
Vì \(\frac{2004}{2005^{2006}+1}
So sánh các phân số
a) 2004/2005 và 2005/2006
b) A= 2005 x 2005 + 1 / 2005 x 2005 x 2005 - 1 và 2005 + 1 / 2005 x 20005 - 1
a) \(\frac{2004}{2005}=1-\frac{1}{2005}\);\(\frac{2005}{2006}=1-\frac{1}{2006}\)
Vì \(\frac{1}{2005}>\frac{1}{2006}\)=>\(1-\frac{1}{2005}< 1-\frac{1}{2006}\)=>\(\frac{2004}{2005}< \frac{2005}{2006}\)
So sánh
A=20052005+1/20052006+1 và B=20052004+1/20052005+1
SO SÁNH A= 20052005 +1/20052006+1 và B =20052004+1/20052005+ 1
Xét A trước ta có
\(A=\frac{2005^{2005}+1}{2005^{2006}+1}\)ta có \(2005.A=\frac{2005.\left(2005^{2005}+1\right)}{2005^{2006}+1}\)
\(2005A=\frac{2005^{2006}+2005}{2005^{2006}+1}\)\(2005A=\frac{2005^{2006}+1+2004}{2005^{2006}+1}\)
\(2005.A=1+\frac{2004}{2005^{2006}+1}\)
Xét B ta có
\(B=\frac{2005^{2004}+1}{2005^{2005}+1}\)ta có \(2005B=\frac{2005\left(2005^{2004}+1\right)}{2005^{2005}+1}\)
\(2005B=\frac{2005^{2005}+2005}{2005^{2005}+1}\)\(2005B=\frac{2005^{2005}+1+2004}{2005^{2005}+1}\)
\(2005B=1+\frac{2004}{2005^{2005}+1}\)
ta có vì 2005A<2005B
từ đó suy ra A<B
nhớ **** đó
1)A=2005^2005+1 trên 2005^2006+1 và B=2005^2004+1 trên 2005^2005 2)A=2006^2006+1 trên2007^2007+1 vàB=2006^2005+1 trên 2006^2006+1
So sánh: \(A=\frac{2005^{2005}+1}{2005^{2006}+1};B=\frac{2005^{2004}+1}{2005^{2005}+1}\)
\(A=\frac{2005^{2005}+1}{2005^{2006}+1}\)
\(\Rightarrow2005A=\frac{2005^{2006}+2005}{2005^{2006}+1}\)
\(\Rightarrow2005A=1+\frac{2004}{2005^{2006}+1}\)
\(B=\frac{2005^{2004}+1}{2005^{2005}+1}\)
\(\Rightarrow2005B=\frac{2005^{2005}+2005}{2005^{2005}+1}\)
\(\Rightarrow2005B=1+\frac{2004}{2005^{2005}+1}\)
Ta thấy \(\frac{2004}{2005^{2005}+1}>\frac{2004}{2005^{2006}+1}\)
Suy ra \(1+\frac{2004}{2005^{2005}+1}>1+\frac{2004}{2005^{2006}+1}\)
hay 2005B>2005A
Vậy B>A