HP 39G User Manual page 24

Trig Explorer
aplet
1-14
The Trig Explorer aplet is used to investigate the behaviour
of the graph of y = a sin
and d change, 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 user presses
in the view, the screen
shown right is displayed.
In this mode, the graph
controls the equation. Pressing
the and keys
transforms the graph, with
these transformations reflected
in the equation.
The button labelled
toggle between and
. When is
chosen, the 'point of control' is
at the origin (0,0) and the
and keys
control vertical and horizontal
transformations. When
is chosen the 'point of control' is on the first extremum of the
graph (i.e. for the sine graph at
The arrow keys change the
amplitude and frequency of the
graph. This is most easily seen
by experimenting.
Pressing displays the
equation at the top of the
screen. The equation is
controls the graph. Pressing the
and keys moves from
parameter to parameter.
Pressing the or key changes the parameter's values.
The default angle setting for this aplet is radians. The angle
setting can be changed to degrees by pressing
bx + c + d as the values of a, b, c
is a
Origin
2 1 , .
Extremum
.
Getting started