HP 50g Graphing Calculator - Manual (Page 421)

Page 12-38
Try also a Wireframe plot for the surface z = f(x,y) = x 2 +y 2
Θ Press „ô, simultaneously if in RPN mode, to access the PLOT SETUP
window.
Θ Press ˜ and type ‘X^2+Y^2’ @@@OK@@@.
Θ Press @ERASE @DRAW to draw the slope field plot. Press @EDIT L@)MENU @LABEL
to see the plot unencumbered by the menu and with identifying labels.
Θ Press LL@)PICT to leave the EDIT environment.
Θ Press @CANCL to return to the PLOT WINDOW environment. Then, press
$ , or L@@@OK@@@, to return to normal calculator display.
Ps-Contour plots
Ps-Contour plots are contour plots of three-dimensional surfaces described by z
= f(x,y). The contours produced are projections of level surfaces z = constant
on the x-y plane. For example, to produce a Ps-Contour plot for the surface z =
x
2 +y 2 , use the following:
Θ Press „ô, simultaneously if in RPN mode, to access to the PLOT
SETUP window.
Θ Change TYPE to Ps-Contour.
Θ Press ˜ and type ‘X^2+Y^2’ @@@OK@@@.
Θ Make sure that ‘X’ is selected as the
Indep:
and ‘Y’ as the
Depnd:
variables.
Θ Press L@@@OK@@@ to return to normal calculator display.
Θ Press „ò, simultaneously if in RPN mode, to access the PLOT
WINDOW screen.
Θ Change the default plot window ranges to read: X-Left:-2, X-Right:2, Y-Near:-1
Y-Far: 1, Step Indep: 10, Depnd: 8
Θ Press @ERASE @DRAW to draw the contour plot. This operation will take some
time, so, be patient. The result is a contour plot of the surface. Notice that
the contour are not necessarily continuous, however, they do provide a
good picture of the level surfaces of the function.