Câu hỏi của ♡๖²⁴ʱƔĄŠℌ๖ۣۜI๖ۣۜR❍ ŇξŇξ 乂 ℌĄŇĄƘ❍༉♡

Question

SO SÁNH $A=\frac{7^{2013}+1}{7^{2014}+1}$VÀ $B=\frac{7^{2014}+1}{7^{2015}+1}$

Nguyễn Ngọc Anh Minh · Accepted Answer

$\frac{A}{B}=\frac{7^{2013}+1}{7^{2014}+1}.\frac{7^{2015}+1}{7^{2014}+1}=\frac{7^{4028}+7^{2013}+7^{2015}+1}{7^{4028}+2.7^{2014}+1}=$

$=\frac{7^{4028}+7^{2013}\left(1+7^2\right)+1}{7^{4028}+2.7.7^{2013}+1}=\frac{7^{4028}+50.7^{2013}+1}{7^{4028}+14.7^{2013}+1}>1$

$\Rightarrow A>B$

Câu trả lời:

$\frac{A}{B}=\frac{7^{2013}+1}{7^{2014}+1}.\frac{7^{2015}+1}{7^{2014}+1}=\frac{7^{4028}+7^{2013}+7^{2015}+1}{7^{4028}+2.7^{2014}+1}=$

$=\frac{7^{4028}+7^{2013}\left(1+7^2\right)+1}{7^{4028}+2.7.7^{2013}+1}=\frac{7^{4028}+50.7^{2013}+1}{7^{4028}+14.7^{2013}+1}>1$

$\Rightarrow A>B$

♡๖²⁴ʱƔĄŠℌ๖ۣۜI๖ۣۜR❍ ŇξŇξ 乂 ℌĄŇĄƘ❍༉♡ · Answer

A/B sao lại nhân v bn

Câu trả lời:

A/B sao lại nhân v bn