Câu hỏi của tien nguyen van

Question

So sánh hai lũy thừa

$\dfrac{n}{n+1}$ và $\dfrac{n+1}{n+3}$

$n\in N\cdot$

Giúp nhé

tien nguyen van · Accepted Answer

Sử dụ ''2'' ta có

$\dfrac{n}{n+1}.\dfrac{n+1}{n+3}=\dfrac{n^2+2n+n}{n^2+2n+1}\ge1.$

Suy ra

$\dfrac{n}{n+1}$ lớn hơn $\dfrac{n+1}{n+3}$ $\in N$

Mk mới học mong các bạn giúp đỡCâu trả lời: Sử dụ ''2'' ta có

$\dfrac{n}{n+1}.\dfrac{n+1}{n+3}=\dfrac{n^2+2n+n}{n^2+2n+1}\ge1.$

Suy ra

$\dfrac{n}{n+1}$ lớn hơn $\dfrac{n+1}{n+3}$ $\in N$

Mk mới học mong các bạn giúp đỡ