In a Cartesian coordinate system (shown in Figure 1), a point p is given by the pair (xp, yp) where xp andyp denote p's location along the horizontal...

In a Cartesian coordinate system (shown in Figure 1), a point p is given by the pair (xp, yp) where xp andyp denote p’s location along the horizontal (x) axis and the vertical (y) axis, respectively. Note that a pointcan lie in any of the four quadrants (I, II, III, and IV), or on either axes, or on the origin (0, 0). Given anytwo points p and q, we let pq denote the line connecting them, shown here in red.