A good answer might be:

| g |  =  (9 + 16 + 1 )  =  26
g_u  =  ( -3, 4, -1)^T / (26)

Opposite Direction

The following represents a unit vector oriented at 45^o:

(1, 1)^T / (2).

The length is ( 1²/2 + 1²/2 ) = 1. The angle is arctan(1/1) = 45^o. How would you make a unit vector that is pointed in the opposite direction? Negate each component:

 -( 1, 1)^T / (2)  =  ( -1, -1)^T / (2).

QUESTION 13:

Create a unit vector that points in the opposite direction as (3, 0, 2)^T.