posted by Heather .
Let L be the line that passes through the points (0,1,6) and (0,3,2). Find the length of the projection of k=<0,0,1> on the line L.
I know how to do this if one part of the vector k is touching the line, but unless i'm mistaken, that is not the case in this question. Your help is very much appreciated!
A vector in the direction of the line is (4, -2, 0)
so let u = (0,0,1) and v = (4,-2,0)
just like before, the projection of u on v = u.v/|v|
= (0+0+0)/√20 = 0
of course the vector (0,0,1) is perpendicular to vector (4,-2,0), so there is no projection
think of "projection" as the shadow that one line casts on the other line, and the above makes sense.