HP 50G, User Manual

Page: 417 / 887

Page 12-34
of y(x,y) = constant, for the solution of y’ = f(x,y). Thus, slope fields are useful
tools for visualizing particularly difficult equations to solve.
Try also a slope field plot for the function y’ = f(x,y) = - (y/x)
2
, by using:
Θ
Press
„ô
, simultaneously if in RPN mode, to access to the PLOT SETUP
window.
Θ
Change
TYPE
to
Slopefield.
Θ
Press
˜
and type ‘
−
(Y/X)^2’
@@@OK@@@
.
Θ
Press
@ERASE @DRAW
to draw the slope field plot. Press
@EDIT L @LABEL
@MENU
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.
Fast 3D plots
Fast 3D plots are used to visualize three-dimensional surfaces represented by
equations of the form z = f(x,y). For example, if you want to visualize z = f(x,y)
= x
2
+y
2
, we can use the following:
Θ
Press
„ô
, simultaneously if in RPN mode, to access to the PLOT SETUP
window.
Θ
Change
TYPE
to
Fast3D.
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
Keep the default plot window ranges to read:
X-Left:-1, X-Right:1, Y-Near:-1, Y-
Far: 1, Z-Low: -1, Z-High: 1, Step Indep: 10, Depnd: 8