So sánh 2 p/số
\(A=\dfrac{2014^{2013}+1}{2014^{2014}+1};B=\dfrac{2014^{2012}+1}{2014^{2013}+1}\)
1. Cho A = \(\dfrac{10^{2013}+1}{10^{2014}+1}\) và B = \(\dfrac{10^{2014}+1}{10^{2015}+1}\). Hãy so sánh A và B
2. so sánh ; 2\(^{332}\) và 3\(^{223}\)
2)Ta có: \(2^{332}< 2^{333}=\left(2^3\right)^{111}=8^{111}\)
\(3^{223}>3^{222}=\left(3^2\right)^{111}=9^{111}\)
Vì \(8^{111}< 9^{111}\) mà \(2^{332}< 8^{111},3^{223}>9^{111}\) nên suy ra \(2^{332}< 3^{223}\)
Vậy \(2^{332}< 3^{223}\)
1) \(A=\dfrac{10^{2013}+1}{10^{2014}+1}\Rightarrow10A=\dfrac{10^{2014}+10}{10^{2014}+1}=\dfrac{10^{2014}+1}{10^{2014}+1}+\dfrac{9}{10^{2014}+1}=1+\dfrac{9}{10^{2014}+1}\)
\(B=\dfrac{10^{2014}+1}{10^{2015}+1}\Rightarrow10B=\dfrac{10^{2015}+10}{10^{2015}+1}=\dfrac{10^{2015}+1}{10^{2015}+1}+\dfrac{9}{10^{2015}+1}=1+\dfrac{9}{10^{2015}+1}\)Vì: \(10^{2014}+1< 10^{2015}+1\Rightarrow\dfrac{9}{10^{2014}+1}>\dfrac{9}{10^{2015}+1}\Rightarrow1+\dfrac{9}{10^{2014}+1}>1+\dfrac{9}{10^{2015}+1}\)
Nên suy ra \(10A>10B\Rightarrow A>B\)
So sánh hai phân số:
A=2014^2013+1/2014^2014+1
B=2014^2012+1/2014^2013+1
So sánh 2 phân số: A= \(\frac{2014^{2013}+1}{2014^{2014}+1}\)và B= \(\frac{2014^{2012}+1}{2014^{2013}+1}\)
Gợi ý nhé: bạn hãy so sánh 2014A và 2014B rồi suy ngược lại A và B
Ta có:
2014A=20142014+ 2014/20142014+1=1+2013/20142014+1
2014B=20142013+2014/20142013+1=1+2013/20142013+1
vì 1+2013/20142014+1<1+2013/20142013+1 nên 10A < 10B
suy ra A<B
So sánh ;A=2014^2013+1/2014^2013-1 va B=2014^2013-1/2014^2013-3.giup mk vs
ta có: \(A=\frac{2014^{2013}+1}{2014^{2013}-1}=\frac{2014^{2013}-1+2}{2014^{2013}-1}=1+\frac{2}{2014^{2013}-1}\)
\(B=\frac{2014^{2013}-1}{2014^{2013}-3}=\frac{2014^{2013}-3+2}{2014^{2013}-3}=1+\frac{2}{2014^{2013}-3}\)
\(\Rightarrow\frac{2}{2014^{2013}-1}< \frac{2}{2014^{2013}-3}\)
\(\Rightarrow1+\frac{2}{2014^{2013}-1}< 1+\frac{2}{2014^{2013}-3}\)
=> A < B
So sánh hai phân số :
A= 20142013+1/20142014+1 và 20142012+1/20142013+1
Tổng S có 50 phân số
=> S > 1/100 + 1/100 + 1/100 +...+ 1/100 (50 phân số) => S > 1/2.
Vậy S > 1/2
so sánh A=2014^2014+1/2014^2015+1 và B=2014^2013+1/2014^2014+1
Có \(2004A=\frac{2014^{2015}+2014}{2014^{2015}+1}=\frac{2014^{2015}+1+2013}{2014^{2015}+1}=1+\frac{2013}{2014^{2015}+1}\)
\(2014B=\frac{2014^{2014}+2014}{2014^{2014}+1}=\frac{2014^{2014}+1+2013}{2014^{2014}+1}=1+\frac{2013}{2014^{2014}+1}\)
Vì \(\frac{2013}{2014^{2015}+1}< \frac{2013}{2014^{2014}+1}\)
=> \(1+\frac{2013}{2014^{2015}+1}< 1+\frac{2013}{2014^{2014}+1}\)
=> \(A< B\)
a, so sánh
M=2013/2014+2014/2015 va N=2013+2014/2014+2015
b, tìm số tự nhiên n sao cho n+3 chia hết cho n^2+1
So sánh hai phân số : A= \(\frac{2014^{2014}+1}{2014^{2013}+1}\) và B= \(\frac{2014^{2013}+1}{2014^{2012}+1}\)
Mình giải như thế này (giải theo công thức) :
Ta thấy A > 1
A=\(\frac{2014^{2014}+1}{2014^{2013}+1}\)> \(\frac{2014^{2014}+1+2013}{2014^{2013}+1+2013}\)= \(\frac{2014^{2014}+2014}{2014^{2013}+2014}\)= \(\frac{2014.\left(2014^{2013}+1\right)}{2014.\left(2014^{2012}+1\right)}=\frac{2014^{2013}+1}{2014^{2012}+1}\)
Vậy A>B
So sánh A và B, biết:
\(A=\dfrac{2014^{2013}+1}{2014^{2014}+1}\) và \(B=\dfrac{2014^{2012}+1}{2014^{2013}+1}\)
\(A=\dfrac{2014^{2013}+1}{2014^{2014}+1}\Leftrightarrow2014A=\dfrac{2014^{2014}+2014}{2014^{2014}+1}=\dfrac{2014^{2014}+1+2013}{2014^{2014}+1}=1+\dfrac{2013}{2014^{2014}+1}\)
\(B=\dfrac{2014^{2012}+1}{2014^{2013}+1}\Leftrightarrow2014B=\dfrac{2014^{2013}+2014}{2014^{2013}+1}=\dfrac{2014^{2013}+1+2013}{2014^{2013}+1}=1+\dfrac{2013}{2014^{2013}+1}\)
Dễ thấy: \(1+\dfrac{2013}{2014^{2014}+1}< 1+\dfrac{2013}{2014^{2013}+1}\) nên \(2014A< 2014B\) hay \(A< B\)