6 So sánh m và n biết
m = \(\frac{2003}{2004}\) + \(\frac{2004}{2005}\) ; n = \(\frac{2003+2004}{2004+2005}\)
giải giùm mình với:
So sánh A và B, biết
\(A=\frac{2003+2004}{2004+2005}\)
\(B=\frac{2003}{2004+2005}\)+\(\frac{2004}{2004+2005}\)
so sánh A và B
A = \(\frac{2003}{2004}+\frac{2004}{2005}\)và B = \(\frac{2003+2004}{2004+2005}\)
\(B=\frac{2003+2004}{2004+2005}=\frac{2003}{2004+2005}+\frac{2004}{2004+2005}\)
Ta có: \(\frac{2003}{2004}>\frac{2003}{2004+2005}\)
\(\frac{2004}{2005}>\frac{2004}{2004+2005}\)
\(\frac{2003}{2004}+\frac{2004}{2005}>\frac{2003+2004}{2004+2005}\)
\(A>B\)
Vậy A>B
\(\text{ Bài giải}\)
\(A=\frac{2003}{2004}+\frac{2004}{2005}=0,999500998 + 0,999501247=1.99900225\)
\(B=\frac{2003+2004}{2004+2005}=\frac{4007}{4009}=0,999501122\)
\(\text{Vì : }1,99900224>0,999501122\text{ nên }A>B\)
\(\text{Vậy : }A>B\)
so sánh M,N
M=\(\dfrac{2003}{2004}+\dfrac{2004}{2005}\)
N=\(\dfrac{2003+2004}{2004+2005}\)
Ta có:
N=\(\dfrac{2003+2004}{2004+2005}\)=\(\dfrac{2003}{2004+2005}\)+\(\dfrac{2004}{2004+2005}\)
Ta thấy:
\(\dfrac{2003}{2004+2005}\)<\(\dfrac{2003}{2004}\)(1)
\(\dfrac{2004}{2004+2005}\)<\(\dfrac{2004}{2005}\)(2)
Từ (1) và (2) --> M=\(\dfrac{2003}{2004}\)+\(\dfrac{2004}{2005}\)>\(\dfrac{2003}{2004+2005}\)+\(\dfrac{2004}{2004+2005}\)=N
Vậy M>N
so sánh A và B
A=\(\frac{20032}{2004}+\frac{2004}{2005}\)và B = \(\frac{2003+2004}{2004+2005}\)
\(A=\frac{20032}{2004}+\frac{2004}{2005}=9,99600798+0,999501247=10,9955092\)
\(B=\frac{2003+2004}{2004+2005}=\frac{4007}{4009}\)
\(\text{Vì : }10,9955092>1\text{ mà }\frac{4007}{4009}< 1\text{ nên }10,9955092>\frac{4007}{4009}\)
\(\text{Vậy : }A>B\)
So sánh:
\(A=\frac{2003}{2004}+\frac{2005}{2006};B=\frac{2003+2004}{2004+2005}\)
so sánh A=\(\frac{2004^{2003}+1}{2004^{2004}+1}\) và B=\(\frac{2004^{2004}+1}{2004^{2005}+1}\)
so sánh A=\(\frac{2004^{2003}+1}{2004^{2004}+1}\) và B=\(\frac{2004^{2004}+1}{2004^{2005}+1}\)
\(2004A=\frac{2004^{2004}+2004}{2004^{2004}+1}=1+\frac{2003}{2004^{2004}+1}\)
\(2004B=\frac{2004^{2005}+2004}{2004^{2005}+1}=1+\frac{2003}{2004^{2005}+1}\)
\(\frac{2003}{2004^{2004}+1}>\frac{2003}{2004^{2005}+1}\)
\(\Rightarrow2004A>2004B\)
\(\Rightarrow A>B\)
2004A=\(\frac{2004^{2004}+2004}{2004^{2004}+1}\)
\(\frac{2004^{2004}+2004}{2004^{2004}+1}-1=\frac{2003}{2004^{2004}+1}\)
2004B=\(\frac{2004^{2005}+2004}{2004^{2005}+1}\)
\(\frac{2004^{2005}+2004}{2004^{2005}+1}-1=\frac{2003}{2004^{2005}+1}\)
Ta thấy :\(\frac{2003}{2004^{2004}+1}>\frac{2003}{2004^{2005}+1}\)
=> \(2004A>2004B\)
Vậy \(A>B\)
so sánh M=\(\frac{2004}{2005}+\frac{2005}{2006}\) và N=\(\frac{2004+2005}{2005+2006}\)
Ta thấy :
2004/2005 >2004/2005+2006
2005/2006> 2005/2005+2006
=> 2004/2005 + 2005/2006 >2004+2005 / 2005+2006
Ta có: \(\frac{2004}{2005}>\frac{2004}{2005+2006}\) (1)
\(\frac{2005}{2006}>\frac{2005}{2005+2006}\) (2)
Từ (1) và (2) => \(\frac{2004}{2005}+\frac{2005}{2006}>\frac{2004+2005}{2005+2006}\) => M>N
Ai k mik mik k lại. chúc các bạn thi tốt
So sánh 2 phân số sau:A=\(\frac{2004^{2003}+1}{2004^{2004}+1}\)và B=\(\frac{2004^{2004}+1}{2004^{2005}+1}\)
Bài này mik nghĩ đáp án là A<B nhưng ko biết giải thích thế nào
Bạn tham khảo nhé
Ta có công thức :
\(\frac{a}{b}< \frac{a+c}{b+c}\) \(\left(\frac{a}{b}< 1;a,b,c\inℕ^∗\right)\)
Áp dụng vào ta có :
\(B=\frac{2004^{2004}+1}{2004^{2005}+1}< \frac{2004^{2004}+1+2003}{2004^{2005}+1+2003}=\frac{2004^{2004}+2004}{2004^{2005}+2004}=\frac{2004\left(2004^{2003}+1\right)}{2004\left(2004^{2004}+1\right)}=\frac{2004^{2003}+1}{2004^{2004}+1}\)
Lại có :
\(A=\frac{2004^{2003}+1}{2004^{2004}+1}\)
\(\Rightarrow\)\(B< A\) hay \(A>B\)
Vậy \(A>B\)
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