Aplet logo APLETS


An Aplet is a neaty-packaged lesson on a mathematical topic. Aplets can take full advantage of the HP calculator capabilities to present explanatory text, plots of different equations, and even graphics to aid in learning.

Aplets can be developed by educators and during class they can be transmitted by cable or infrared ports to the students' calculators. Then the students can use the Aplet to explore the subject matter in class or at home.

The Aplets are controlled by a group of keys placed left from the cursor keys.

Aplet keys HP39G+ Aplet keys HP40G
Aplet keys of the HP 39G+
Aplet keys of the HP 40G

An Aplet is build from the next components:

  • Type:
    Every Aplet is based on one of the predefined Aplet types: Function, Parametric, Polar, Sequence, Solve and Statistics. The type affects the kind of equation that appears in the [SYMB] list.

  • Equations:
    You can store up to ten equations as part of an Aplet. The equation's type (statistics, parametric, polar, etc.) is dictated by the Aplet's type as described above. To view or edit the list of equations, press [SYMB].

  • Note view:
    This view appears when you press [NOTE]. This view contains only a textual description.

  • Sketch view:
    This view appears when you press [SKETCH]. The Aplet's sketch can contain up to 10 pages of graphics that illustrate the Aplet or its equations.

  • View menu:
    This view appears when you press [VIEWS]. The views menu contain selections for different types of plots, based on the Aplet type.


Example of an Aplet

A nice example of an Aplet is the Aplet called PolySides. It is designed to explore how a regular polygon can approximate a circle as the number of sides increases. This Aplet can be downloaded here.

The Aplet must be uploaded to the Aplet Library. On start, the next screen series is displayed.

aplet1 aplet2 aplet3

The first screen gives a short introduction, the second screen asks for a radius and the third screen displays the calculated results for a perfect circle.


What will be displayed on the Note and the Sketch pages?

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The Note view for this Aplet is shown by the first two screen dumps. The third screendump shows the Sketch view.


The central point of departure for PolySides is [VIEWS]. The next menu will popup.



The Side Lenghts, Perimeter and Area items will result in a plot of this parameter as a > function of the number of sides. Functions F1, F2 and F3 are given in the NOTE view.

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The equations can be displayed by the SYMB view. This results in the next screen. This screen also shows that this Aplet is build from type Function.



The functions can be viewed in a more readable way by selection of the function and pressing the SHOW softkey.

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The Polygon Props item in the list of the [VIEWS] pops up a screen where a number of sides can be entered. By typing 21, this results in the next screens with calculated results.

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The [PLOT] and [NUM] keys can also be used to plot the functions or display lists of results.

The building of this Aplet is described in The Hewlett Packard Journal of June 1996, entitled Creating HP 38G Aplets.


Links related to Aplets