The SYMB, PLOT and NUM keys
The
APLET
key is used to choose between the various different aplets
available. Everything in the calculator revolves around aplets, which you can
think of either as miniature programs or as environments within which you can
work.
The hp 39gs and hp 40gs come with twelve standard aplets - Finance,
Function, Inference, Parametric, Polar, Linear Solver, Triangle Solver,
Quadratic Explorer, Sequence, Solve, Statistics and Trig Explorer.
Which one you want to work with is chosen via the
APLET
key. See
page 14 for more details on this.
Calculator Tip
HOME
too. See page 28.
The name of the active aplet is shown at the top of the screen, as
above. It is important to bear this in mind because the angle and
numeric settings are tied to the active aplet. Changing aplets may
therefore cause these settings to change in
In addition to the standard twelve, covered in great detail in the chapters following, many more aplets are
available from the Internet written by other programmers. Once these are downloaded into your calculator
they can also be accessed via the
APLET
key. For more detail on this type of aplet, see the brief summary
later in this section, and the chapter entitled “Programming the hp 39gs & hp 40gs” on page 255.
When working mathematically there are three ways that we view functions:
•
symbolically, as an equation;
•
numerically, as a table;
•
graphically, as a graph in various formats.
The
SYMB
,
PLOT
and
NUM
keys are intended to reflect this common
methodology. In most aplets the
PLOT
view shows the graph, the
SYMB
view shows the equations and the
NUM
view shows the
equations in tabular (numeric) format.
20