An intuitive derivation of Stirling's formula is presented, together with a modification that greatly improves its accuracy. The derivation is based on the closed form evaluation of the gamma function at an integer plus one-half. The modification is easily implemented on a hand-held calculator and often triples the number of significant digits…

This article describes a solution, using CAS, to graph theory problem that was presented in the movie "Good Will Hunting."

Introducing any new initiative into teaching involves professional development and training. This paper investigates the reactions of three teachers to the introduction of graphics calculators into their department. Each teacher was followed through one academic year. They were interviewed formally on two occasions and also met informally with the…

Many popular mathematical software products including Maple, Mathematica, Derive, Mathcad, Matlab, and some of the TI calculators produce incorrect graphs because they use complex arithmetic instead of "real" arithmetic. This article expounds on this issue, provides possible remedies for instructors to share with their students, and demonstrates…

This paper was developed with the goal of enhancing the mathematical preparation of secondary school teachers in the technological paradigm. It shows how two-variable inequalities can be utilized as models for the construction of geometric objects using the software Graphing Calculator 3.5 (produced by Pacific Tech) as a relation grapher. An…

This research examines students' use of graphics calculators and investigates the extent to which the students' use meets their teachers aim when using graphics calculators in the classroom. The teacher's use of her graphics calculator was analysed over a week using Key Record software. The teacher was questioned about her aims and expectations…

This paper provides an instrumental account of precalculus students' graphical process for solving polynomial inequalities. It is carried out in terms of the students' instrumental schemes as mediated by handheld graphing calculators and in cooperation with their classmates in a classroom setting. The ethnographic narrative relays an instrumental…

An eighth grade algebra class used graphing calculators to simulate ecosystems. One simulation introduced mathematical chaos. The activities exposed the students to nonlinear patterns and modeling. The rate-of-change investigations related the ideas of intercept and slope to the changing equilibrium. The chaotic model intrigued them and was useful…

This article offers an engaging application that adds meaning to the binomial theorem. (Contains 8 figures.)

Since the 1999 fall semester, the TI-92 Plus or the TI-89 has been a compulsory purchase for new students entering one engineering school in Montreal, Canada (almost 1000 enrolments a year). The purpose of this paper is to share impressions of a campus-wide experience and to communicate solutions adopted to help students and faculty members in the…

Computer Algebra Systems (CAS) can be used to help understand the behavior of cubics and other families of curves. The analysis of the parameters associated with a family of curves can give insight into the behavior of the family and can be used within the context of a mathematical model to determine a policy for the implementation of the model in…

This study investigated the effects of using the TI-92+ calculator to demonstrate geometric diagrams to students in class. The participants (N=83) were from three 10th grade classes. A pretest, treatment, posttest with control group design was used in the study. The treatments lasted for 12 weeks. Results from data analyses via the Dependent…

Explores the effects of varying the coefficients in the general quadratic function using graphing calculators. (MKR)

Presents examples in which the graphing calculator can provide students with particularly valuable insights into some major statistics ideas such as random numbers. (ASK)

Describes a calculator program that graphs and indicates the main features of the conic whose second-degree equation includes a nonzero xy-term. The program indicates coefficients of conic in a rotated coordinate system, type of conic, angle of rotation, coordinates of vertices of conic in the original coordinate system, and a graph of conic…