Relations and Functions Lesson 2-1 Relations and Functions

Relation – set of pairs of input and output values. You can write a relation as a set of ordered pairs. (0,10), (1,13), (2,16), (3,19) What would the graph of a relation look like.

Domain- set of all inputs or x – coordinates of the ordered pairs Range- the set of all outputs, or y- coordinates of the ordered pairs Find the domain and range of the relation (2,4), (3,4.5), (4,7.5), (5,7), (6,5), (6, 7.5)

Mapping diagram- links elements of the domain with corresponding elements of the range. (0,10), (1,13), (2,16), (3,19) 0 10 1 13 2 16 3 19

A function is a relation in which each element of the domain is paired with exactly one element in the range. 2 5 -1 -3 3 6 0 7 4 8 1 10 7

You can tell if a relation is a function by its graph. Vertical line test- if a vertical line passes through at least two points on the graph, the relation is not a function. Ex) 4 on pg 23

A functional rule expresses an output value in terms of an input value. Examples of functional rules. y = 2x f(x) = x + 5 C = ∏d Output Input

Functional notation f(x) is read “f of x” Note that f(x) does not mean f times x. f(x) = 2x + 3 You can make ordered pairs using the rule. Find f(2) and f(-½)

Assignment 2-44 even, 63 on pg 59-60