HP 40g hp 39g+ (39g & 40g)_mastering the hp 39g+_English_E_F2224-90010.pdf - Page 167

The Trig Explorer Teaching Aplet, Objectives, SIN vs. COS, SYMB vs. GRPH mode

Page 167 highlights

THE TRIG EXPLORER TEACHING APLET Rather than being a multi-purpose aplet like most of the others covered so far, this is a teaching aplet specialized to the single use of exploring the graphs of trigonometric functions. Objectives Using the Trig Explorer aplet, the student will investigate the behaviour of the graph of y = a sin(bx + c) + d as the values of a, b, c and d change. This can be done both by manipulating the equation and seeing the change in the graph, or by manipulating the graph and seeing the change in the equation. When the student presses , they will see the main screen of the aplet, shown right. Like the Quadratic Explorer, this aplet has only one screen, rather than the usual PLOT, SYMB and NUM 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 shown. SIN vs. COS The (or ) key can be used to toggle between the y = sin ( x) curve and the y = cos ( x) curve. The (or ) key can be used to toggle between radian measure and degree measure. The markings on the horizontal axis adjust accordingly (see right). SYMB vs. GRPH mode The Trig Explorer aplet can be used in two modes: SYMB mode - the equation controls the graph (press the SYMB key). and PLOT mode - the graph controls the equation (press the PLOT key). Which mode is in operation is controlled by pressing the SYMB and the PLOT keys. The NUM key has no effect in this aplet and the aplet has no SETUP views. The ranges for the x and y axes are preset and cannot be changed. In both modes the original shape of the sine or cosine graph is left visible as a dotted line for comparison. 167

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167
T
HE
T
RIG
E
XPLORER
T
EACHING
A
PLET
Rather than being a multi-purpose aplet like most of the others covered so
far, this is a teaching aplet specialized to the single use of exploring the
graphs of trigonometric functions.
Objectives
Using the Trig Explorer aplet, the student will investigate the behaviour of the
graph of
sin(
)
y
a
bx
c
d
=
+
+
as the values of
a
,
b
,
c
and
d
change.
This can be
done both by manipulating the equation and seeing the change in the graph,
or
by manipulating the graph and seeing the change in the equation.
When the student presses
, they will see
the main screen of the aplet, shown right.
Like
the Quadratic Explorer, this aplet has only one
screen, rather than the usual
PLOT
,
SYMB
and
NUM
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 shown.
SIN vs. COS
The
(or
)
key can be used to
toggle between the
(
)
sin
y
x
=
curve and the
(
)
cos
y
x
=
curve. The
(or
) key can
be used to toggle between radian measure
and degree measure.
The markings on the
horizontal axis adjust accordingly (see right).
SYMB vs. GRPH mode
The Trig Explorer aplet can be used in two
modes:
SYMB
mode
- the equation controls the graph (press the
SYMB
key).
and
PLOT
mode
- the graph controls the equation (press the
PLOT
key).
Which mode is in operation is controlled by pressing the
SYMB
and the
PLOT
keys.
The
NUM
key has no effect in this aplet and the aplet has no
SETUP
views.
The ranges for the x and y axes are preset and cannot be changed.
In both modes the original shape of the sine or
cosine graph is left visible as a dotted line for
comparison.