So sánh n/n+1 và n+2016/n+2017
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(A=\frac{n+2016}{n}=\frac{n}{n}+\frac{2016}{n}\)
\(B=\frac{n+2017}{n+1}=\frac{n+1+2016}{n+1}=\frac{n+1}{n+1}+\frac{2016}{n+1}=1+\frac{2016}{n+1}\)
Vì \(1=1\);\(\frac{2016}{n}>\frac{2016}{n+1}\)nên \(1+\frac{2016}{n}>1+\frac{2016}{n+1}\)hay \(A>B\)
Vậy \(A>B\)
\(A=\frac{n+2016}{n}=\frac{n}{n}+\frac{2016}{n}=1+\frac{2016}{n}\)
\(B=\frac{n+2017}{n+1}=\frac{\left(n+1\right)+2016}{n+1}=1+\frac{2016}{n+1}\)
Vì \(n< n+1\) nên \(\frac{2016}{n}>\frac{2016}{n+1}\) => \(1+\frac{2016}{n}>1+\frac{2016}{n+1}\)
Do đó A > B
\(11M=\frac{11^{2016}+11}{11^{2016}+1}=1+\frac{10}{11^{2016}+1}\)
\(11N=\frac{11^{2017}+11}{11^{2017}+1}=1+\frac{10}{11^{2017}+1}\)
Vi \(\frac{10}{11^{2016}+1}>\frac{10}{11^{2017}+1}\) nen 11M > 11N => M > N
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)
Ta có : \(\frac{n}{n+1}+\frac{1}{n+1}=1\)
\(\frac{n+2016}{n+2017}+\frac{1}{n+2017}=1\)
Mà : \(n+1< n+2017\Rightarrow\frac{1}{n+1}>\frac{1}{n+2017}\)
nên : \(\frac{n}{n+1}< \frac{n+2016}{n+2017}\)
N = \(\frac{2016+2017}{2017+2018}=\frac{2016}{2017+2018}+\frac{2017}{2017+2018}\)
Ta có: \(\frac{2016}{2017}>\frac{2016}{2017+2018}\)
\(\frac{2017}{2016}>\frac{2017}{2017+2018}\)
Nên M > N
Ta thấy : \(\frac{2016+2017}{2017+2018}\)=\(\frac{2016}{2017+2018}\)+\(\frac{2017}{2017+2018}\)
Vì : \(\frac{2016}{2017}\)>\(\frac{2016}{2017+2018}\)
\(\frac{2017}{2018}\)>\(\frac{2017}{2017+2018}\)
Cộng vế với vế ta được : \(\frac{2016}{2017}\)+\(\frac{2017}{2018}\)> \(\frac{2016}{2017+2018}\)+\(\frac{2017}{2017+2018}\)
Hay M > N
Vậy M > N
Chúc bạn hok tốt !!
\(\frac{n}{n+1}\)và \(\frac{n+2016}{n+2017}\).
Ta có:
\(\frac{n}{n+1}=\frac{n+1-1}{n+1}=1-\frac{1}{n+1}\)
\(\frac{n+2016}{n+2017}=\frac{n+2017-1}{n+2017}=1-\frac{1}{n+2017}\).
Ta lại có:
\(\frac{1}{n+1}>\frac{1}{n+2017}\forall n\).
\(\Rightarrow\frac{-1}{n+1}< \frac{-1}{n+2017}\forall n\).
\(\Rightarrow1-\frac{1}{n+1}< 1-\frac{1}{n+2017}\forall n\).
Do đó \(\frac{n}{n+1}< \frac{n+2016}{n+2017}\).
Vậy....