Question

so sánh 

A= 10¹¹-1/ 10¹² -1 và B= 10¹⁰ +1/ 10¹¹+1

C= 10⁹⁹ +5/ 10⁹⁹ -8 và D= 10¹⁰⁰+6/ 10¹⁰⁰-4

Answer 1

1/

\(10A=\frac{10^{12}-10}{10^{12}-1}=1-\frac{9}{10^{12}-1}<1\)

\(10B=\frac{10^{11}+10}{10^{11}+1}=1+\frac{9}{10^{11}+1}>1\)

$\Rightarrow 10A< 1< 10B$

$\Rightarrow A< B$

Answer 2

2/

\(C=\frac{10^{99}+5}{10^{99}-8}=1+\frac{13}{10^{99}-8}\)

\(D=\frac{10^{100}+6}{10^{100}-4}=1+\frac{10}{10^{100}-4}\)

So sánh \(\frac{13}{10^{99}-8}=\frac{130}{10^{100}-80}> \frac{130}{10^{100}-4}> \frac{10}{100^{100}-4}\)

$\Rightarrow 1+\frac{13}{10^{99}-8}> 1+\frac{10}{100^{10}-4}$

$\Rightarrow C> D$