Consider the points P(3,–2), Q(3,5), R(–4,1) and S(4,1).
(i) Find the slope of the line PQ and comment on its nature.
(ii) Find the slope of the line RS.
(iii) Show that the lines PQ and RS are perpendicular to each other.
(iv) Determine the coordinates of the point where the line RS cuts the y-axis.