Question

So sánh:A=\(\frac{10^{12345}+1}{10^{12346}+1}\) 

          B=\(\frac{10^{12344}+1}{10^{12345}+1}\)

Answer 1

Ta có công thức : 

\(\frac{a}{b}< \frac{a+c}{b+c}\)\(\left(\frac{a}{b}< 1;a,b,c\inℕ^∗\right)\)

Áp dụng vào ta có : 

\(A=\frac{10^{12345}+1}{10^{12346}+1}< \frac{10^{12345}+1+9}{10^{12346}+1+9}=\frac{10^{12345}+10}{10^{12346}+10}=\frac{10\left(10^{12344}+1\right)}{10\left(10^{12345}+1\right)}=\frac{10^{12344}+1}{10^{12345}+1}=B\)

\(\Rightarrow\)\(A< B\)

Vậy \(A< B\)

Chúc bạn học tốt ~ 

Answer 2

Ta có : A = \(\frac{10^{12345}+1}{10^{12346}+1}< 1\)

=> A < \(\frac{10^{12345}+1+9}{10^{12346}+1+9}=\frac{10^{12345}+10}{10^{12346}+10}=\frac{10^{12344}+1}{10^{12345}+1}\)= B

Vậy A < B