Hi BlaXpydo
I assume you talk about the 2010 Oct/Nov Exam. I agree with you that the diagram looks incorrect and also the textual answer in the memorandum. I have the 2006 Handbook and if you look on page 333 Section 7.4.3 you will see they state:
p1 = [x1, y1] p2= [x2,y2]
So I believe you are correct that P should be (x1, y1) and Q (x2,y2) and thus we also need to fix the first line of the answer from:
"Suppose we have a line segment defined by two endpoints p (x1, y1) q(x1, y1)."
to
"Suppose we have a line segment defined by two endpoints p (x1, y1) q(x2,y2). "
Hope this helps (and are correct)