Question

Rút gọn:

\(a.\sqrt{x}.\sqrt{\dfrac{1}{x}}\left(x>0\right)b.\sqrt{\dfrac{-1}{y}}.\sqrt{\dfrac{y^3}{-4}}\left(y< 0\right)\)

Answer 1

a: \(=\sqrt{x\cdot\dfrac{1}{x}}=1\)

b: \(=\sqrt{\dfrac{-1}{y}\cdot\dfrac{y^3}{-4}}=\sqrt{\dfrac{y^2}{4}}=-\dfrac{y}{2}\)

Answer 2

a)\(\sqrt{x}\cdot\sqrt{\dfrac{1}{x}}=\sqrt{x}\cdot\dfrac{\sqrt{1}}{\sqrt{x}}=\dfrac{\sqrt{x}.\sqrt{x}}{x}=\dfrac{x}{x}=1\) `(x>0)`

b)\(\sqrt{\dfrac{-1}{y}.}\sqrt{\dfrac{y^3}{-4}}=\sqrt{-\dfrac{y^3}{-4y}}=\sqrt{\dfrac{y^2}{4}}=-\dfrac{y}{2}\left(y< 0\right)\)