# How do you find a unit vector of i-3j?

##### 1 Answer
Jul 10, 2016

$= \frac{1}{\sqrt{10}} i - \frac{3}{\sqrt{10}} j .$

#### Explanation:

For a given non-null vctr. $\vec{v}$, unit vctr. in its direction is given by, $\frac{\vec{v}}{|} | \vec{v} | |$.

For our $\vec{v} = i - 3 j \ne \vec{0}$, we have $| | \vec{v} | | = \sqrt{{1}^{2} + {\left(- 3\right)}^{2}} = \sqrt{10}$

Hence, the reqd. unit vector$= \frac{1}{\sqrt{10}} i - \frac{3}{\sqrt{10}} j .$