I have this question. I'll go through the previous parts so you have an idea of what it's asking.
Given u = (4, 0, -2), v = (3, 1, -1), w = (2, 1, 6) find
(a) the angle between u and w (98 degrees)
(b) the component of u along v (14/11)
(c) the projection of v along w 1/41(2,1,6) i.e (2/41, 1/41, 6/41)
And finally (d) a vector constructed from (c) and perpendicular to w
I'm struggling with this final part... I just don't understand it..