XFunctions is a general-purpose program for playing with mathematical functions. It is not meant for use in scientific analysis or for making presentation-type graphs and charts. It was written primarily to help students learn mathematics. A major goal in writing the program was to make it as easy as possible to use, so that students can concentrate on learning about mathematics, rather than learning about computers. It is also fun just to play with (at least if you are mathematically inclined).
I wrote the program xFunctions primarily for use in Calculus and pre-Calculus courses. In courses that I teach, it is used in a lab setting (where the students have immediate access to help), in combination with problem sets that encourage the students to explore concepts and then to write about what they have learned.
Interesting features include: New functions can be input as either single formulas, split functions, graphs, or tables. A knife tool can be used to cut out a rectangle on a graph for enlargement. Seven special "utility" operations include: graphing several graphs on one set of axes; animation of a family of functions of the form f(x,k); graphing of derivatives and tangent lines; Riemann sums, with graphical display; graphs of parametrically defined curves; integral curves of vector fields; and three-dimensional plots of functions z = f(x,y); A limited printing facility is provided. Files can be saved containing utility examples and functions that you input. (A sample file of examples should accompany this program.) An "Info" menu is available when the program is run to give full information on the program and the seven utilities.
The version I am distributing will work on any Macintosh. I have another version that requires a Macintosh with a 68020 or 68030 processor and math coprocessor (Mac IIcx, IIci, SE/30, Quadra, etc.). I will be happy to send you a copy of this program, by E-mail in BinHex format or on a floppy disk. At some point in the future, a collection of lab exercises based on xFunctions might be available. Comments, inquiries and bug reports are welcome.
