I want to ask about Unidirectional vectors
Assume that I've vector u = [7 6 -3]
and I've vector v in the same direction as u with initial point A= (2,-1,4)
so is it enough to say that v=K[7 6 -3]
or I've to say that B= A + v = (2+7k,6k-1, 4-3k)
Generally speaking, a vector is an equivalence class of 'objects' that have the same length and same direction. As such, the notion of initial point is mute. By that is meant, starting at any point 'moving off' in the same direction with the same length gives the same vector.
Vectors are parallel if they are non-zero multiples of each other.
They have the same direction if the multiple is positive.