HP 48g Graphing Calculator - Manual (Page 325)

Note that the three-dimensional coordinate system on the HP 48
is somewhat constrained compared to its abstract, mathematical
counterpart. Specifically:
■ The plot display screen does not rotate in space; it always stays
parallel to the »z-plane and perpendicular to the y-axis. This means
that, visually, “height” is always along the z-axis, “width” along the
a;-axis, and “depth” along the y-axis.
m The y-axis is always oriented so that negative ?/-values are “nearer”
and positive ?/-values “farther” away from the plot display.
B The eyepoint must be at least one unit “nearer” than y„ear
{Ve < Vnear ^ 1) and Can never exist “within” the View Volume.
Whenever you move the eyepoint, you also move the plot display
screen so that it remains exactly one unit away in the direction of
the y-axis.
■ You cannot plot a “top” view of a function (looking down onto the
a;y-plane) simply by moving the eyepoint. (You may simulate this
by transforming coordinates, however.)
23
Slopefield Plots
The Slopefield plot type draws a lattice of line segments whose slopes
represent the value of the function, f(x,y), at their centerpoint.
Using Slopefield allows your eye to pick out integral curves of the
differential equation y' = F{x, y). It is quite useful in understanding
the “arbitrary constant” in antiderivatives.
The Default SLOPEFIELD Plot Screens
PLPTÍ
TYPE: Slopefield Deg
EQ:
INBEP: K STEPS: 10
DEPNO: Y STEPS: 0
ENTER FUNCTiaHtS}_TD PLOT___________
^^^PLDT DPTIDNS
X-LEFT: BBWi 1 X-RIGHT: 1
V-NEftR: -1 Y-FRR: 1
ENTER MINIMUM X VIEW-VOLUME VRL
Plot Types 23-25