Maxima and computer algebra use in STACK
STACK uses the computer algebra system (CAS) Maxima and a graphical desktop interface like wxMaxima can be helpful for ofline editing, including a STACK-Maxima sandbox for testing question code on the desktop.
Computer algebra systems are most often designed for either the research mathematician, or the student to do calculations. For the purposes of assessment our calculation establish some relevant properties of the students' answers. Establishing properties in this way, and on the basis of this creating outcomes such as feedback, is something particular to assessment systems. Such properties include things like
- is the expression algebraically equivalent to the correct answer?
- is the expression fully simplified?
- is the expression written a particular conventional form, (e.g. factored, partial fraction)?
- are all the numbers in the expression written as fractions in the lowest terms?
Maxima in STACK
- Predicate functions, which are useful to test expressions.
- Numbers, including floating point and complex numbers.
- Simplification can be switched on and off in Maxima.
- Matrices and vectors.
- Randomly generated objects.
- Plots and graphics.
- Buggy rules implements rules which are not always valid!