I. BASICS 
FUNCTIONS AND GRAPHS 
Change to Full Graphics 
A function is relation between variables. 
Variable y is a function of variable x if to each value of the variable x corresponds one value of the variable y. We then write: y = f(x) 

The symbol f( ) stands here for some mathematical expression as for example: f(x) = x + 1 
Function can be also called transformationof one variable into the otheror mapping of one set of numbers into the other. 
The righthand variable x is also called an independent variable because its values can be changed arbitrarily. The lefthand variable y is then the dependent variable because its value depends on the value of the variable x. 
Functions with one independent variable are called univariate. There are also multivariate functions with several independent variables. A multivariate function with n independent variables is written as y = f(x_{1},x_{2},x_{3},....,x_{n}) 
.



