a)có tử và mẫu lớn hơn thì lớn hơn!

b)có tử,mẫu lớn hơn thì bé hơn!

c)tương tự câu a

đúng 100%

\(C=\frac{\frac{2006}{2}+\frac{2006}{3}+\frac{2006}{4}+....+\frac{2006}{2007}}{\frac{2006}{1}+\frac{2005}{2}+\frac{2004}{3}+.....+\frac{1}{2006}}\)

Đặt N = \(\frac{2006}{1}+\frac{2005}{2}+\frac{2004}{3}+.....+\frac{1}{2006}\)

\(\Rightarrow N=\frac{1}{2006}+.....+\frac{2004}{3}+\frac{2005}{2}+\frac{2006}{1}\)

\(\Rightarrow N=\left(\frac{1}{2006}+1\right)+.....+\left(\frac{2004}{3}+1\right)+\left(\frac{2005}{2}+1\right)+1\)( Có 2005 nhóm )

\(=\frac{2007}{2006}+....+\frac{2007}{3}+\frac{2007}{2}+\frac{2007}{2007}\)
\(=2007\left(\frac{1}{2}+\frac{1}{3}+.....+\frac{1}{2006}+\frac{1}{2007}\right)\)

Đặt M = \(\frac{2006}{2}+\frac{2006}{3}+\frac{2006}{4}+....+\frac{2006}{2007}\)

\(=2006\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+.....+\frac{1}{2007}\right)\)

Thay N và M vào C , ta có :

\(C=\frac{N}{M}=\frac{2006\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+.....+\frac{1}{2007}\right)}{2007\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+....+\frac{1}{2007}\right)}=\frac{2006}{2007}\)

\(\Rightarrow C=\frac{2006}{2007}\)

Vậy : \(C=\frac{2006}{2007}\)

mik ko bít

I don't now

................................

.............

ko bít thì đừng comment :))

\(\frac{2004}{2005}+\frac{2005}{2006}\)

\(=1-\frac{1}{2005}+1-\frac{1}{2006}=2-\left(\frac{1}{2005}+\frac{1}{2006}\right)\)

\(\frac{2004+2005}{2005+2006}=\frac{2004}{2005+2006}+\frac{2005}{2005+2006}\)

Ta có: \(\frac{2004}{2005+2006}<\frac{2004}{2005}\)

\(\frac{2005}{2005+2006}<\frac{2005}{2006}\)

Do đó: \(\frac{2004}{2005+2006}+\frac{2005}{2005+2006}<\frac{2004}{2005}+\frac{2005}{2006}\)

2004 /2005*(+2005) /2006 < 2004*(+2005) /2005 +2006