What is Computer Algebra System?
A '''computer algebra system (CAS)''' is a large [[computer program]] that helps people with [[mathematics]] and [[algebra]]. It changes and moves around (manipulates) mathematical [[equation]]s and expressions containing [[number]]s and symbols called [[variable]]s. Variables can stand for known or unknown values that can be solved for, or can be replaced with any value. It always keeps the formula exactly the same mathematically as the original equation or expression, unless it is being transformed, by a transformation algorithm. A CAS might be used for [[integral|integration]] or [[derivative (mathematics)|differentiation]] (and other [[calculus]] transformations), simplification of an expression (making it smaller and/or simpler), optimizing and finding the minimum and maximum values of results or variables, etc. Most have the ability to [[Cartesian coordinate system|plot functions and expressions]] for visualization, which can be helpful and educational too. ==Symbolic capabilities== Computer algebra systems can be special purpose, focusing on only a few types of symbolic math, to very large, general purpose programs that do almost everything (for example, the [[free software|free]] CAS Maxima,<ref>[http://maxima.sourceforge.net/ Maxima, a Computer Algebra System]</ref> which is the oldest CAS that is still under development). The results output by a good computer algebra system are often exact, simple, and generalized to work in all possible cases. Computer programs do have [[software bug|bugs]], so important results should always be verified for correctness. ==Numeric capabilities== Modern computer algebra systems often include extensive numeric capabilities for convenience and which fit together with its symbolic abilities. Numeric domains supported often include [[real number|real]], [[complex number|complex]], [[interval (mathematics)|interval]], [[rational number|rational]], and algebraic numbers. Usually [[Floating point unit|floating point]] arithmetic is available to use if desired, because