Question

the vector \[e_v\] is a unit vector of v I guess
\[\vec v=<3,-1>\]

\[||v||=\sqrt{9+1}=\sqrt{10}\]
so
\[e_v=\frac{1}{||v||} \vec v=\left <\frac3{\sqrt{10}},\frac{-1}{\sqrt{10}}\right >\]

Answer 1

How did I do?

Answer 2

seems all right!!

Answer 3

Thank you!

Answer 4

hardly a probs :)