Vector magnitude

Classical Mechanics

Find the unit vector in the direction of $5 i +j - 2 k.$

5 i + j - 2 k

\frac{5}{30}i+\frac{1}{30}j-\frac{2}{30} k

\frac{5}{\sqrt{30}}i+\frac{1}{\sqrt{30}}j-\frac{2}{\sqrt{30}} k

None of the above