This is the summary of a presentation given at the Joint Mathematics Meetings, January 10-13, 1996, Orlando, Florida.

We demonstrate the instructional routine lincombo that we wrote in version 4 of MATLAB to teach linear combinations in a beginning linear algebra course. The opening screen of lincombo displays graphically two basis vectors u and v in two-space chosen at random, and a third random vector w. The student uses sliders to intuitively determine coefficients c1 and c2 such that w = c1 u + c2 v. The aim is to produce sufficient experience to gain familiarity with this concept and to understand related concepts.

This approach provides integration of ideas and gives students a familiar tool to use for new situations. We indicate how we have used lincombo to enrich classroom presentations of the parallelogram law of addition of vectors, span, and coordinates of a vector relative to different bases.

David E. Zitarelli, Temple University
David R. Hill, Temple University