So, the title is: Parallel Vectors: Is AP Parallel to u?

[LCKurtz]

Way back in the OP, the question was, "Is the vector $\vec{AP}$ parallel to u?" Apparently the coordinates of P were not given (or at least, they weren't shown in this thread). I believe the answer would be showing the conditions on the coordinates of P, something like this:
p₁ = ...
p₂ = ...
p₃ = ...

And, of course, that's assuming we have guessed correctly what the actual statement of the problem was supposed to be n the first place.

 

[Mark44]

And, of course, that's assuming we have guessed correctly what the actual statement of the problem was supposed to be n the first place.

Well, there's that...