HP 50G, User Manual

Page: 421 / 887

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.