Frequently Asked Questions

Which browsers work best with GraphFree?

To use as many of GraphFree’s features as possible, recent versions of Firefox and Chrome are the best choices at this time.

Versions of Internet Explorer older than version 9 will not work at all, and there are other reasons to prefer Firefox and Chrome for this site. One program tested (Smart Notebook 11) was not able to paste graphs directly from Internet Explorer using copy and paste, though it handled graphs from Firefox and Chrome correctly. Also, Internet Explorer does not support dashed line plots until version 11. (Asymptotes drawn with the Plot type set to Asymptote will still appear as dashed lines. It is only the ability to use dashed lines for the ordinary Function Plot type that requires version 11.)

As for mobile browsers, we’re not ready to promise a great experience yet, but we hope to create a tablet-friendly version of this site in the future.

How do I get the graphs from GraphFree into my word processor, presentation program, etc.?

You should always be able to right-click the graph and click “Save Image As” (Firefox, Chrome) or “Save Picture As” (Internet Explorer) to save the graph to your hard drive in PNG format. Nearly all programs will allow you to import or insert a PNG image.

Most programs will also allow you to use the faster method of copying and pasting the image, though some programs are particular about how images from GraphFree are pasted. To copy the image, right-click the graph and click “Copy” (Internet Explorer) or “Copy Image” (Firefox, Chrome). The procedures for pasting a graph from GraphFree into some common programs are shown in the table below. The versions listed are simply the ones we happened to use in our tests; other versions of the same program will usually work similarly.

ProgramProcedure to Paste from GraphFree
Microsoft Word 2010Use the “Paste Special” command from the ribbon and select “Device Independent Bitmap.”
Microsoft PowerPoint 2010Select the “Paste as Picture” option. This option is available when you right click in PowerPoint’s work area or select the “Paste” drop down button from the ribbon. The keyboard shortcut CTRL-V will not work.
SMART Notebook 11The standard paste operations using the keyboard shortcut CTRL-V or the “Paste” command from the menu bar work if you are using Firefox or Chrome. If, however, you are using Internet Explorer, then you will need to save the graph to your hard drive as described above and use the “Import -> Picture” command from the menu.
Adobe InDesign CS4Standard pasting operations (CTRL-V, right-click and “Paste,” etc.) work.
Adobe Photoshop CS4Standard pasting operations (CTRL-V, right-click and “Paste,” etc.) work.
OpenOffice Writer 4.1Use the “Paste Special” command from the “Edit” menu and select “Bitmap.”
OpenOffice Impress 4.1Standard pasting operations (CTRL-V, right-click and “Paste,” etc.) work.

How do I graph a circle, ellipse, or hyperbola?

For conic sections such as these (and other equations that have not been solved explicitly for y), change the Plot type setting to Implicit. This will activate the X, Y, and = buttons on the button pad so that you can enter the equation. The example below shows how to graph an ellipse.

How can I graph a parabola that opens to the left or right?

This is another situation where you need to set the Plot type to Implicit. Then use the newly enabled Y and = buttons (along with X) to enter the equation, as shown below.

Can I use GraphFree to create blank grids for tests, quizzes, etc.?

Absolutely. Just choose the grid options you want from the panel in the lower right. In the section for specific plot information, leave everything blank.

How can I graph a vertical line?

There are a couple of different ways to do this, depending on your intent. If you want to show a vertical asymptote, set the Plot type to Asymptote. Then select Vertical from the Direction menu, and fill in the value for X. This will produce a graph with a dashed line, as is traditional for an asymptote.

If you want a solid vertical line instead, then set the Plot type to Implicit, and enter the equation of the line, for example, X = 5.

How do I add my own labels, annotations, etc. to my graph?

You can add any text you wish—labels of ordered pairs, explanations, etc.—using the options in the Set Custom Note Texts tab.

From within this tab, you can add text for up to six custom notes. Once you create the plot, you can use the mouse to drag the notes into position. Additional screen shots of this process can be found in the User’s Guide.

Why is there occasionally a solid vertical line where there should be an asymptote? (And can I fix it?)

Like other graphing calculators, GraphFree works by evaluating a function at various values of x to create a list of ordered pairs, then connecting the points. Sometimes, two consecutive points shouldn’t really be connected because they’re on opposite sides of a vertical asymptote. GraphFree tries to detect these situations, and it succeeds more often than not. Unfortunately, perfection requires a full-blown computer algebra system, so GraphFree won’t catch them every time. When it misses one, a nearly vertical line can appear where there should really be a break in the graph.

Fortunately, it’s often possible to fix this behavior when it occurs. One way to do this is by tweaking the xMin, xMax, or Plot width settings. Tweaking any of these options will change the values of x that GraphFree uses for its table of points, possibly letting the asymptote detection algorithm succeed again.

Another method is to graph over a smaller range of y values by changing yMax, yMin, or both. When the yMax and yMin values are closer together, the asymptote detection algorithm becomes more sensitive, possibly eliminating the errant vertical line.

Why don’t single points and other small features show up when I use the Implicit plot type?

Implicit types require a large number of calculations to perform, and this process could be extremely slow if GraphFree were programmed to detect very small features. Therefore, features of an Implicit plot that are smaller than a few pixels across may not appear. In some cases, you may get a better view of such features if you use larger Plot width and Plot height settings. You should not expect to see single points at any size, however, since the detection of single points generally requires a computer algebra system.