# How do you find a unit vector that has the same direction as the given vector −5i + 9j?

$\textcolor{w h i t e}{\text{XXX}}$unit vector: $\textcolor{g r e e n}{- \frac{5}{\sqrt{106}} i + \frac{9}{\sqrt{106}} j}$
$\textcolor{w h i t e}{\text{XXX}} \left\mid - 5 i + 9 j \right\mid = \sqrt{{\left(- 5\right)}^{2} + {9}^{2}} = \sqrt{25 + 81} = \sqrt{106}$