+x+y+z- x
–y- z
Figure 18-1 Cartesian three-space. The x axis increases positively
from left to right, the y axis increases positively
from the bottom up, and the z axis increases
positively from far to near. All three axes intersect at
the origin and are mutually perpendicular.P
(–5,–4,3)Q
(3,5,–2)+x+y+z
- x
–y- z
Each axis
increment
is 1 unitFigure 18-2 Two points in Cartesian three-space, along with the
corresponding ordered triples of the form (x,y,z). On all
three axes, each increment represents 1 unit.
291