# Presentation of the CAS

## Introduction

The CAS (Computer Algebra System) was developed for the CASIO FX-9860. It's a small application which is added in the main menu of your calculator. You can use this application by selecting the new icon in your menu :

The operations that can be realized with this application are detailed in the followings parts of this page.

## Derivative calculus

The CAS allows you to differentiate any expression. Expressions you want to differentiate can have more than one variable, and then you have to indicate the variable you want to use.

Example :
diff(2x^2+3x+2,x) will derivate the expression 2x^2+3x+2 using x as the derivative variable. Then the result will be 4x+3.

## Expand an expression

The CAS allows you to expand any expression. If you want to expand an expression which contain more than one variable, you have to indicate which variable you want to use.

## Simplification

The CAS allows you to simplify any expression. In particular, it allow to simplify trigonometric expression.

## Solving

The CAS have a solver module which allow to solve equations (linear or not). If your unknown variable is not x, you have to indicate which variable you want to use to solve the equation.

## Decomposition

The CAS have a function which allow to decompose any number as a product of prime numbers.

## GCD calculus

The CAS allows you to determine very quickly the GCD (Greatest common divisor) of two numbers.