Question

so sánh: 7/10²⁰¹⁵+15/10²⁰¹⁶ và 7/10²⁰¹⁶+15/10²⁰¹⁵

Answer 1

Lời giải:

$\frac{7}{10^{2015}}+\frac{15}{10^{2016}}-(\frac{7}{10^{2016}}+\frac{15}{10^{2015}})$

$=\frac{-8}{10^{2015}}+\frac{8}{10^{2016}}=8(\frac{1}{10^{2016}}-\frac{1}{10^{2015}})<0$

$\Rightarrow \frac{7}{10^{2015}}+\frac{15}{10^{2016}}< \frac{7}{10^{2016}}+\frac{15}{10^{2015}}$