Answer
$\frac{-2\sqrt{5}}{5}i+\frac{\sqrt{5}}{5}j.$
Work Step by Step
If $v=ai+bj$ then the unit vector $u$ in the direction of $v$ is $u=\frac{v}{||v||}$, where $||v||=\sqrt{a^2+b^2}.$ $||v||=\sqrt{(-2)^2+1^2}=\sqrt{5}.$
Hence $u=\frac{-2i+j}{\sqrt{5}}=\frac{\sqrt{5}(-2i+j)}{5}=\frac{-2\sqrt{5}}{5}i+\frac{\sqrt{5}}{5}j.$
