So sánh C= \(\frac{2013}{2014}+\frac{2014}{2015}\)
và D=\(\frac{2013+2014}{2014+2015}\)
a) So sánh \(\frac{2013}{2015}\) và \(\frac{2014}{2016}\)
b) So sánh \(\frac{2013+2014}{2014+2015}\) và \(\frac{2013}{2014}+\frac{2014}{2015}\)
a)\(\frac{2013}{2015}< \frac{2014}{2016}\)
b)\(\frac{2013+2014}{2014+2015}< \frac{2013}{2014}+\frac{2014}{2015}\)
ta có tính chất \(\frac{a}{b}\)>1 suy ra \(\frac{a.m}{b.m}\).........
so sánh
\(\frac{2013}{2014}+\frac{2014}{2015}và\frac{2013+2014}{2014+2015}\)
Ta có: \(\frac{2013}{2014}>\frac{2013}{2014+2015}\) (1)
\(\frac{2014}{2015}>\frac{2014}{2014+2015}\) (2)
ộng caác bất đẳng thứa (1) và (2) vào vế với vế:
\(\frac{2013}{2014}+\frac{2014}{2015}>\frac{2013+2014}{2014+2015}\Rightarrow A>B\)
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So sánh:
\(\frac{2013}{2014}+\frac{2014}{2015}+\frac{2015}{2016}\)và\(\frac{2013+2014+2015}{2014+2015+2016}\)
1) CMR : A=(n+2015)(n+2016) + n2 + n chia hết cho 2 với n ϵ N
2) So sánh :
P = \(\frac{2013}{2014^{2013}}+\frac{2014}{2015^{2014}}+\frac{2015}{2016^{2015}}+\frac{2016}{2017^{2016}}\) và
Q = \(\frac{2014}{2017^{2016}}+\frac{2013}{2016^{2015}}+\frac{2016}{2015^{2014}}+\frac{2015}{2014^{2013}}\)
A = (n + 2015)(n + 2016) + n2 + n
= (n + 2015)(n + 2015 + 1) + n(n + 1)
Tích 2 số tự nhiên liên tiếp luôn chia hết cho 2
=> (n + 2015)(n + 2015 + 1) chia hết cho 2
n(n + 1) chia hết cho 2
=> (n + 2015)(n + 2015 + 1) + n(n + 1) chia hết cho 2
=> A chia hết cho 2 với mọi n \(\in\) N (đpcm)
So sánh C và D , biết :
C = 2013/2014 + 2014/2015
D = \(\frac{2013+2014}{2014+2015}\)
Các bạn giải rõ ra hộ mk nha
D=2013+2014/ 2014+2015
D= 2013/2014+2015 + 2014/2014+2015
2013/2014+2015 < 2013/2014
2014/2014+2015 < 2014/2015
suy ra 2013/2014+2015 +2014/2014+2015 < 2013/2014+ 2014/2015
hay D < C ( ĐPCM)
XONG NHA BẠN !@!!!!!!!!!!!!!!!!!!!!chắc chắn đúng lun
1. So sánh M và N ( Ko Quy Đồng)
biết M = \(\frac{2012}{2013}+\frac{2013}{2014}+\frac{2014}{2015}\)và
N =\(\frac{2012+2013+2014}{2013+2014+2015}\)
( Giải rõ ràn nha) tớ tick cho
\(N=\frac{2012+2013+2014}{2013+2014+2015}=\frac{2012}{2013+2014+2015}+\frac{2013}{2013+2014+2015}+\frac{2014}{2013+2014+2015}\)
Ta thấy: \(\frac{2012}{2013}>\frac{2012}{2013+2014+2015}\)
\(\frac{2013}{2014}>\frac{2013}{2013+2014+2015}\)
\(\frac{2014}{2015}>\frac{2014}{2013+2014+2015}\)
\(\Rightarrow M=\frac{2012}{2013}+\frac{2013}{2014}+\frac{2014}{2015}>N=\frac{2012}{2013+2014+2015}+\frac{2013}{2013+2014+2015}+\frac{2014}{2013+2014+2015}\)
Vậy M>N
Cho M=\(\frac{2013}{2014}+\frac{2014}{2015}\)
N=\(\frac{2013+2014}{2014+2015}\)
So sánh M và N
Ta có:
\(\frac{2013}{2014}>\frac{2013}{2014+2015}\)
\(\frac{2014}{2015}>\frac{2014}{2014+2015}\)
\(\Rightarrow\frac{2013}{2014}+\frac{2014}{2015}>\frac{2013+2014}{2014+2015}\)
\(\Rightarrow M>N\)
Ta có: \(N=\frac{2013+2014}{2014+2015}<1\);
\(M=\frac{2013}{2014}+\frac{2014}{2015}>\frac{2013}{2015}+\frac{2014}{2015}=\frac{4027}{2015}>1\)
\(\Rightarrow A>B\)
TA CÓ
2013>\(\frac{2013}{2014+2015}\)
2014>\(\frac{2014}{2014+2015}\)
=>2013+2014/2014+ 2015>2013+2014/2014+2015
=>M>N
\(\frac{2013}{2014}+\frac{2014}{2015}+\frac{2015}{2013}\). hãy so sánh với 3
http://olm.vn/hỏi-đáp/question/85092.html, bạn ấn vào đây có bài y chang luôn !
Tính:
\(\frac{1}{1+\frac{2013}{2014}+\frac{2013}{2015}}+\frac{1}{1+\frac{2014}{2015}+\frac{2014}{2013}}+\frac{1}{1+\frac{2015}{2013}+\frac{2015}{2014}}\)