1. 2-1 Relations and Functions
Big Idea:
-Determine if a set of values is a relation.
-Determine if a relation is a function.

2. Vocabulary
Relation: a set of pairs of input and output values. (x, y)

3. Ex 1: Graph each relation
{(0,2), (1, 3), (2, 4)}

4. B) {(-½, 3), (-4, -1), (5, 0)}

5. Domain: of a relation is a set of all inputs, or the x-coordinates of the ordered pairs.
Range: of a relation is the set of all outputs, or y-coordinates of the ordered pairs.

6. Ex 2: Write the ordered pairs for each relation
Ex 2: Write the ordered pairs for each relation. Find the domain and range.
A( , )
B( , )
C( , )
D( , )
E( , )
F( , )
Domain:
Range:

7. Making a mapping diagram
A way of showing a relation that links the domain to the range. (x to y)

8. Ex 3: Make a mapping diagram for each relation.
B) {(10, -5), (-4, 1), (0, 0), (4, -5)}

9. Function: a relation in which each element of the domain is paired with exactly one element in the range. y x

10. Ex 4: Determine whether each relation is a function.
B) {(0, 5), (11, -7), (10,5)}
C) {(2, 6), (6, 2), (0,0), (-2, 12)}

11. Ex 5: Use the vertical-line test to determine whether the graph represents a function.
A) B)

12. C) D)

13. Ex 6: For each function, find f(-2), f(½), f(3).
A) f(a) = 3a + 9
B) f(x) = -2x + ½