# The Variable Eq; Three-dimensional Graphics; Examples Of Interactive Plots Using The Plot Menu - HP 50g User Manual

Graphing calculator.

### Three-dimensional graphics

The three-dimensional graphics available, namely, options Slopefield,
Wireframe, Y-Slice, Ps-Contour, Gridmap and Pr-Surface, use the VPAR variable
with the following format:
{x
, x
left
right
x
, y
, z
eye
eye
These pairs of values of x, y, and z, represent the following:
Dimensions of the view parallelepiped (x
z
, z
low
high
Range of x and y independent variables (x
Location of viewpoint (x
Number of steps in the x- and y-directions (x
Three-dimensional graphics also require the PPAR variable with the parameters
shown above.

## The variable EQ

All plots, except those based on DAT, also require that you define the function
or functions to be plotted by storing the expressions or references to those
functions in the variable EQ.
In summary, to produce a plot in a program you need to load EQ, if required.
Then load PPAR, PPAR and PAR, or PPAR and VPAR. Finally, use the name of
the proper plot type: FUNCTION, CONIC, POLAR, PARAMETRIC, TRUTH,
DIFFEQ, BAR, HISTOGRAM, SCATTER, SLOPE, WIREFRAME, YSLICE,
PCONTOUR, GRIDMAP, or PARSURFACE, to produce your plot.

### Examples of interactive plots using the PLOT menu

To better understand the way a program works with the PLOT commands and
variables, try the following examples of interactive plots using the PLOT menu.
Example 1 – A function plot:
„ÌC
@) P TYPE @FUNCT
' r' `„ @@EQ@@
, y
, y
near
far
, x
, y
eye
step
)
, y
eye
, z
, z
, x
low
high
}
step
left
min
)
, z
eye
eye
Get PLOT menu (*)
Select FUNCTION as the plot type
Store function ' r' into EQ
, x
, y
min
max
, x
, y
right
, x
, y
max
min
)
, y
step
step
, y
,
min
max
, y
,
near
far
)
, y
max
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