Chapter 10 - Section 10.5 - Rationalizing Numerators and Denominators of Radical Expressions - Exercise Set - Page 717: 2

$\dfrac{\sqrt{5}}{\sqrt{2}}=\dfrac{\sqrt{10}}{2}$

$\dfrac{\sqrt{5}}{\sqrt{2}}$ Multiply the fraction by $\dfrac{\sqrt{2}}{\sqrt{2}}$ and simplify: $\dfrac{\sqrt{5}}{\sqrt{2}}=\dfrac{\sqrt{5}}{\sqrt{2}}\cdot\dfrac{\sqrt{2}}{\sqrt{2}}=\dfrac{\sqrt{10}}{\sqrt{2^{2}}}=\dfrac{\sqrt{10}}{2}$