The Quad Explorer Teaching Aplet - HP 39gs Master Manual

T Q E
T Q E
H E U A D X
H E U A D X
Rather than being a multi-purpose aplet, this is a teaching aplet specialized to the single use of exploring
graphs of quadratics. As such it does not have the normal
multi-purpose view.
Objectives
Using the Quadratic Explorer aplet, the student will investigate the behavior of the graph of y
as the values of a, h and v change. This can be done both by manipulating the equation and seeing the
change in the graph, and by manipulating the graph and seeing the change in the equation.
Press to see the main screen of the aplet, shown right. This aplet
has only the one screen, rather than the usual
views. If the aplet has been used before then it may be necessary to
press the screen key to go back to the opening view.
Choosing the level
The first choice made by the user should be the
level is that of Y=a(X+h)
parameters at once. By having the student choose the levels of Y=aX
Y=(x+h) 2 or Y=X 2 +v, the teacher can confine the study to the effects of
only one coefficient at a time if desired.
GRAPH mode
The default state for the aplet is to be in
student uses the keys listed below to control the appearance of the
graph, with these changes reflected automatically in the two equations
on the right half of the screen. The original y=x
screen (dotted) for comparison and a grid is supplied to allow the user to
see movement more clearly.
The control keys (listed onscreen) are:
and
T
T
P L O R E R E A C
P L O R E R E A C
PLOT
+v , which allows the student to change all
2
move the graph in the obvious way.
cycle the value of 'a' in y=a(x+h)
the values 0.1, 0.2, 0.3, 0.5, 1, 2 & 5. No other
values are possible.
(the 'negative' key) changes the sign on the
'a' coefficient turning the graph upside down.
A
A
H I N G P L E T
H I N G P L E T
,
SYMB NUM
, and
SYMB NUM
. The default
2 ,
mode. In this mode the
2 graph is kept on the
2 +v through
159
and views, but only a single
PLOT
=
a x h
27
( )
2
+ + v