ABSTRACT
The simplest method is to attach a label to the desired point, along the
lines of “You are here.” This method is purely geometric, but not much
help in computations. One standard way to label points is to choose a
coordinate system, such as rectangular coordinates, and to give the values
of the chosen coordinates at the desired point. Thus, we might write
P = (x, y) (2.1)
to define a particular point P in the plane with coordinates (x, y). This
method works just as well when using other coordinate systems (such as
polar coordinates in the plane) or on a sphere (most likely using spherical
coordinates).
