1-1 RELATIONS & FUNCTIONS What is a relation? What is a function? Function notation Writing and graphing functions Lesson Essential Question: How do we determine if a relation is a function?

What is the difference between a relation and a function? A relation is a set of ordered pairs. Example: {(1,6), (2,7), (2,8),(4,9)} A function is a set of ordered pairs in which each element in the domain pairs with exactly one element in the range. Example: {(1,6), (2,7), (3,8),(4,9)}

Practice… Example #1 Example #2

How can you tell it is a function given a graph? Vertical Line Test – If every vertical line drawn on the graph passes through no more than one points of the graph, then it is a function.

Function Notation y = 2x + 3 is the same as f(x) = 2x + 3 f(x) = y Example #3 Evaluate f(3) if f(x)= 2x + 5 Evaluate g(-1) if g(x)= -x3 – 2 Evaluate h(-2) if h(x) = |3x+1|

In Class Work / Homework In Book: pg 10, #11-53 odds