I did it another way. Does this work?

I took the vector given (the one that mine follows in the same direction). Then I converted it to a unit vector with magnitude 1. I multiplied the unit vector by a scalar of the magnitude given to come up with a new vector.

Then I separated that new vector into components.

Are the components I'm looking for:
a) The x, y, and z values when the vector has the tail at the origin?

or

b) The x, y, and z values of the tip?

I think the tail information is irrelevant.