HP 39g+ - Manual (Page 24)

1-14 Getting started
Trig Explorer
aplet The Trig Explorer aplet is used to investigate the behaviour
of the graph of
as the values of a, b, c
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 TU6SU—
in the 6QG@U— view, the screen
shown right is displayed.
In this mode, the graph
controls the equation. Pressing
the
*k,*e, and *>,*A, keys
transforms the graph, with
these transformations reflected
in the equation.
The button labelled PSDB—— is a
toggle between PSDB—— and
@YUS—— . When PSDB—— is
chosen, the ‘point of control’ is
at the origin (0,0) and the
*k,*e, and *>,*A, keys
control vertical and horizontal
transformations. When
@YUS——
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
>6<0%@ displays the
equation at the top of the
screen. The equation is
controls the graph. Pressing the
*A, and *>, keys moves from
parameter to parameter.
Pressing the
*k, or *e, 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
S69—— .
y a bx c +
( )
d + sin =
Origin
π
2 1 ,
⁄ ( )
Extremum