The !Diffn Software Application is an x Expression Differentiating program for the Acorn RISC OS Wimp environment, and is available for free download.

Hopefully, should be 26/32-bit neutral.

After having downloaded and unzipped the !Diffn Application, drag the application to a suitable directory on your hard disc. Double click on the !Diffn icon to load it onto the icon bar.

Left click on the bar icon, and the 'SetUp' panel will be displayed.

Select options from the 'SetUp' panel, in particular supply an expression in x in the upper slot, and then click on the 'Calculate' icon. The differential is returned in the lower slot, or a warning message if the expression has not been understood.

The differential can be moved back to the upper slot, for re-differentation, or the 'Roots' (Turning Points) of the differential can be determined.

You can end, by closing the window, or by choosing 'Reset' from the icon bar menu to return to default settings.

This Version 3.00 now admits of functions (EXP, COS or SIN) of functions (EXP, COS or SIN). Still a bit 'buggy'!

Additional Help is available from the bar icon menu, or by using the Acorn facility !Help, present in the 'Apps' directory.

Read the '!ReadMe1st' file present in the zipped file for information on the known 'bugs', and the file '!ReadMe' within the application (double click over the application icon with 'Shift' held down to find it), for conditions of use.

Click on Icon to DownLoad Zipped !Diffn 32-bit compatible Version 3.00 Dated July 26th 2009.