Using GeoGebra

GeoGebra 3.2 is available for download or web start by clicking here.  For your own computer, you might as well download and install GeoGebra.  When you work in a computer lab, use web start.

GeoGebra is free, runs well, and allows you to make high quality graphics easily.  It is particularly well-suited to making graphics of lines, points, functions, derivatives, and integrals.

• Step by step directions for using GeoGebra to graph a piecewise function  See the dynamic worksheet.  Download the worksheet
• Using GeoGebra to graph a polynomial (or other function) with arrows indicating that the graph continues but is not shown  Download the worksheet
• Using GeoGebra to graph a rational function with horizontal and vertical asymptotes  Download the worksheet

Exporting a GeoGebra worksheet as a web page

To save your worksheet as a webpage, pull down File, Export, Dynamic Worksheet as Webpage, then fill in the title for the page, text you want to go above the worksheet, and text you want below.  I recommend that you click the Advanced tab and click all the boxes so that the GeoGebra window in the worksheet will have full GeoGebra capabilities.  Finally, click Export.  GeoGebra will prompt you for a name for the .html file and where you want to put it.  Probably you want to save it in a GeoGebra subfolder of your public_html folder.  In addition to the .html file, GeoGebra may also save a geogebra.jar file and a .ggb file specific to the worksheet you made.  Remember not to use spaces in the filename because personal.bgsu.edu will not accept them.

Linear regression

Version 3.2 has support for linear regression.  Very briefly, input a dataset this way:  M = {(1,2),(2,2),(3,4),(5,4)}.  This is the list of data points.  By right clicking it in the list of free objects, you can Show Object.  Then, input L = FitLine[M] and GeoGebra will put a linear regression line L through the datapoints.  Better yet, input P=(1,2) then Q=(2,2) and R=(3,5), then M = {P, Q, R}, then W = FitLine[M].  Now you can move the points around and the regression line will follow!

Miscellaneous

• To change the number of decimal places, pull down Options, Rounding.  You can have up to fifteen decimal places.
• If you want a picture with a larger font, larger arrows, etc., make the GeoGebra window on your computer smaller (resize the window), then re-adjust the graph to get the size you want.  For instance, you might want to make the window this small:
  

Difficulties with exporting image files in previous versions of GeoGebra

• You can export the drawing pad as a pdf, and this seems to work well.  However, it is not totally easy to incorporate a PDF image into Word without loss of image quality.

• When exporting the graph as encapsulated postscript (.eps), you must carefully set the "Scale in cm" entries.  As far as I can tell, modifying them (and then clicking in the other field) updates the "Size" line.  For GeoGebra 3.0, your goal is to make the first size number, the horizontal size, as close to 21.59 cm (8.5 in) as possible without going over.  In this case, you can use 3.1:1.  In other cases, I have had to use 1:2.2.  Experiment to get the right combination.  If the size is larger than 21.59, the right part of the image will be cut off.  If less than 21.59, the image will be very small, and quality will suffer.  For GeoGebra 3.2, I have not yet figured out the best scale to use.

  

  Click Export and choose a file name.  You can put this into Word with Insert, Picture, From File.  When printed or converted to PDF, it will be high quality.

• From the dynamic worksheet (html file with drawing pad, etc.) you can't export to .eps, as far as I can tell.

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