Answer
$\frac{\sqrt{5}}{5}$.
Work Step by Step
The given expression is
$=\frac{1}{\sqrt{5}}$
Multiply by $\frac{\sqrt{5}}{\sqrt{5}}$.
$=\frac{1}{\sqrt{5}}\cdot \frac{\sqrt{5}}{\sqrt{5}}$
Use product property of square roots.
$=\frac{\sqrt{5}}{\sqrt{5\cdot 5}}$
$=\frac{\sqrt{5}}{\sqrt{5^2}}$
Simplify.
$=\frac{\sqrt{5}}{5}$.
