Question

Ánh Lê

So sánh (không dùng QDMS)

a) \(\dfrac{12}{13}và\dfrac{122}{132}\)

b)\(\dfrac{-15}{7}và\dfrac{-23}{11}\)

c)\(\dfrac{12^{190}+1}{12^{191}+1}và\dfrac{12^{191}+1}{12^{192}+1}\)

Answer 1

a ) b) Không biết làm đâu :))
c)

Đặt \(A=\dfrac{12^{190}+1}{12^{191}+1};B=\dfrac{12^{191}+1}{12^{192}+1}\)

\(12A=\dfrac{12^{191}+12}{12^{191}+1}=1+\dfrac{11}{12^{191}+1}\)

\(12B=\dfrac{12^{192}+12}{12^{192}+1}=1+\dfrac{11}{12^{192}+1}\)

\(\Rightarrow12A>12B\Leftrightarrow A>B\)