Activities 1. How many planes can we form using the axes in space? What are they? 2. What are the physical meanings of the coordinates of a point P (x, y,z) on the space ? 3. Plot points (1,0,1),(-1,2,1), and (1,-1,-1) on the space. As the coordinate axes in a two-dimensional coordinate system divide 2-space into four quadrants, the coordinate of three-dimensional coordinate system divides 3-space into eight parts, called octants. To obtain a formula for distance between two points in 3-space, consider P(47.91, -,) and Q(x2,92,2) which are points in 3-space. * Z QUX-Y2,22) 122- 211 PR X2 -- Xi P(x, y,z) y2-y! ►Y O 2 х