 ## Computer Algebra System (CAS) A Computer Algebra System (CAS) is a software program that facilitates symbolic mathematics. The core functionality of a CAS is manipulation of mathematical expressions in a symbolic form.

The HP CAS system was created by Bernard Parisse, University de Grenoble, for the HP 48GII, HP 49G+ calculators and later in HP 50G graphing calculator. The same CAS technology was later implemented on the HP 40G and HP 40GS. The HP CAS system offers the user a vast array of functions and abilities as well as an easy user interface.

The expressions manipulated by the CAS typically include polynomials in multiple variables; standard functions of expressions (sine, exponential, etc.); various special functions (gamma, zeta, erf, Bessel, etc.); arbitrary functions of expressions; derivatives, integrals, sums, and products of expressions; truncated series with expressions as coefficients, matrices of expressions, and so on.

Some examples of exact calculations:
Calculation Result HP 40G Result numeric
(3/2 - 1) / (1/2 +1 ) 1/3 0.33333333
2√45 + 3√12 - √20 - 6√3 4√5 8.94427191
SIN ( pi / 4)   √2/2 0.70710678

Some examples of symbolic calculations:

Calculation Result CAS
FACTOR ( X^2 - 2) (X+√2).(X - √2)
(5+4i).(2-3i)  22 - 7i  