downloadable files

A demo version of Omnigraph is available for download. Go to the Download page for details. Contact SPA if you wish to purchase it. You can also download some files that can be loaded into it. This is a developing area of MathsNet. You may have files yourself that could be made available to other users. Make contact if you have.
For MathsNet Omnigraph files, move to the Download... page.

link with TI-82/3 calculators

The Texas Instruments calculators TI-82 and TI-83 both have some graph and coordinate plotting functions that are similar to Omnigraph. In the last year or two, more and more students studying mathematics at A-Level or similar have purchased such graphic calculators, so that, whereas only a few might have Omnigraph at home, most will have the calculator. It therefore seems like a good idea to make some resources for investigating mathematics common to both media.

With this in mind you will find by moving to the Download... page some files that can be loaded in your TI calculator. They are essentially identical to files contained in "Investigations with Omnigraph" mentioned above.

MEI users group

An M.E.I. Technology Working group on Omnigraph was set up in June 1996.
The contact is:

- reviewed

Omnigraph for Dos, probably the best educational software on graph processing, has been around for a number of years. Now SPA has published the Windows version, which is currently at Version 2:

It loads and runs very quickly in Windows 3.1. Though the concepts of calculus and other higher level mathematics are readily available, the greatest single strength of Omnigraph has always been that you can load it up and type in y=2x+1 and get a graph displayed at once. This remains true in the Windows version. The biggest improvement after that is the replacement of the confusing "Options" menu of the Dos version by the conventional Windows menu system - though there are no icons yet. Maybe there's no need. All the previous options are still available - you can even load the same old Dos files into it. It will load csv format files too (a format most spreadsheets can save in), which immediately opens up the potential for using Omnigraph for data handling. MathsNet will be creating soon some csv data files for this purpose.

There are new options too - the most important being the ability to enter implicit equations (x²+y²=9 for example) and inequalities. The program's ability to cope with implicit equations is good but you may have to wait and put up with some strung-out points if the equation is too complicated. Complicated functions can be entered and displayed in correct format, for example (x+1)/(x+2) will appear in correct fractional notation.

Other developments include much improved coordinate handling. Single points can be readily added or deleted. In addition to zooming in and out and rescaling, you can now "grab" the whole graph and slide it about. Drag a tangent line along a curve and see it surf up and down the slope changing its gradient appropriately. There is a "demonstration" mode whereby curves are drawn slowly by a computer pencil, and lines can be thickened to make them more visable in the classroom.

I would imagine that the "Power series" option in the Dos version was rarely used; now there is an improvement in that you can define a series by its nth term. The series
y=1 + x + x²/2! + ... is entered by
nth=x^n-1/(n-1)!

Clicking on the curve highlights its equation - a nice new touch! - but what would be brilliant is the facility to alter the shape of the curve with the mouse whilst its equation is continuously updated in the Equations Window. Can we have that in Version 3 please?

Overall though, an excellent program has got even better.

dynamic constants

animations

Using the Transformations options together with the Repeats command, you can produce precise mathematical transformations of geometric shapes too. First create a shape or a curve. Then select Transformations from the menu bar, and then, for example, a Rotation. To create an animation of a 360 degree rotation about the origin, you will need enter an animation of 0.1 degrees and Repeat it 3600 times. You could Repeat a 1 degree rotation 360 times but Omnigraph may display this too quickly.

The display in the equations window at the bottom of the screen should be something like:

construction lines

You can add all kinds of construction lines to your diagrams. First create a curve. Then select the Analysis option from the menu bar. You can then add horizontal or vertical lines, either right across the graph (good for showing asymptotes) or from the axes to the curve itself. You can add tangent or normal lines too, and if you are studying calculus, you can show the curves of the gradient and area functions (illustrating differentiation and integration).

inequalities

You can illustrate inequalities of both implicit and explicit functions. Before entering the equations, select Custom and change the accuracy to say 500, but be aware that the higher this number the slower Omnigraph will be in redrawing these graphs. Under Customise curve you can choose your own colours too.
The inequality symbols can be inserted using the Edit menu then Insert.

latest version

Autumn 2000 Version 2.1a

• Minor update

Summer 1999 Version 2.1

• A minor update to allow the new interactive Omniguide facility to work.
• Customisable toolbar and screen layout
• Full use of function notation
• Predrawn shapes

September 1998 Version 2

A Toolbar

A customisable toolbar for quick access to all the most common menu items.

Coordinate editor

The coordinate editor now gives even an better and easier way to enter a coordinate shape.

All editors now work proper maths:

Editors in the rescale, custom curve and coordinate editor dialog boxes now accept full maths notation including superscript and fractions etc.

Rescale:

The rescale dialog box now allows you to choose the curve you want to use for autoscale.

Custom

New features added to enhance your control of the appearance of Omnigraph.

Custom curve

You can now enter the hidden description and chose the curve from inside the custom curve dialog box. You can also chose from the full range of colours your computer offers.

Dynamic constants

Wow!! See the effect of changing a variable dynamically before your very eyes. No need now to explain the effect of a in the equation y=a sinx!

Defined functions

Now you can simply define a function by typing it in.

Editing a curve with secondaries

You can now edit a curve which has secondaries. e.g. If you have drawn a coordinate shape and reflected it, you can go back to the coordinate editor and change the shape. Watch the reflection change as you move the points around! You cannot change the type of curve in this situation.

March 1997 Version 1.0C