What is a Function?
- A function is a sort of "machine" that outputs one y value for every value of x in its domain.
- The set of possible x values is called the domain of a function.
- The set of y values that the domain is mapped to is called the range of the function.
- Since y values (output) depend on the x values (input) y is called the dependent variable, and x is the independent variable.
- The independent variable can also be called the argument of the function.
- While x and y are often used as paired variables for relations and functions, any set of variables can actually be used!
Relations
- Technically all functions are relations, yet not all relations are functions.
- A relation R is a set of ordered pairs, (x,y) such a that x ∈ A and y ∈ B where sets A and B are non-empty.
- A function f is a relation in which every x-value has a unique y-value.
Sources
https://300math.weebly.com/day-3---functions--relations.html