Từ giả thiết: \(1\ge x+\dfrac{1}{y}\ge2\sqrt{\dfrac{x}{y}}\Rightarrow\dfrac{x}{y}\le\dfrac{1}{4}\Rightarrow\dfrac{y}{x}\ge4\)
\(\Rightarrow A=2\left(\dfrac{16x}{y}+\dfrac{y}{x}\right)+\dfrac{2020y}{x}\ge2.2\sqrt{\dfrac{16xy}{xy}}+2020.4=8096\)
\(A_{min}=8096\) khi \(\left(x;y\right)=\left(\dfrac{1}{2};2\right)\)