Find a unit vector u in the direction opposite of ⟨−3,−9,−9⟩.

Answer 1

go east instead of west
go north instead of south
go up instead of down
so unit vector in direction of (3 , 9 , 9 )
sqrt(9+2*81) = sqrt171
so
(3/sqrt171 , 9/sqrt171 , 9/sqrt171)