HP 40G manual Trig Explorer aplet, A, keys

Trig Explorer aplet

The Trig Explorer aplet is used to investigate the behaviour of the graph of y = a sin (bx + c) + d 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 67$57a in the $3/(7aview, 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 25,*a￿ais
toggle(;75a￿abetween25,*a￿aand
. When	is	Origin
chosen, the ‘point of control’ is
at the origin (0,0) and the
*k,*e, and *>,*A, keys
control vertical and horizontal
transformations. When (;75a￿a

is chosen the ‘point of control’ is on the first extremum of the graph (i.e. for the sine graph at (π ⁄ 2,1) .

The arrow keys change the
amplitude and frequency of the	Extremum
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 5$'a￿a.

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