[tex]\it y = \dfrac{1}{x}, \ \ \ x = \sqrt2
\\ \\ \\
\dfrac{x}{\dfrac{1}{x}} +\dfrac{\dfrac{1}{x}}{x}= {x^2+\dfrac{1}{x^2} =2+\dfrac{1}{2} = \dfrac{5}{2}[/tex]
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[tex]\it \dfrac{x}{y} +\dfrac{y}{x} = \dfrac{x^2+y^2}{xy} = \dfrac{(\sqrt2)^2+\left(\dfrac{1}{\sqrt2}\right)^2}{\sqrt2\cdot\dfrac{1}{\sqrt2}}=\dfrac{2+\dfrac{1}{2}}{1}=\dfrac{5}{2}[/tex]
