1. 3-2 Representing Functions
Function: A relation in which each element of the domain is paired with exactly one element of the range
Not a Function
Function

2. Functions
Without graphing you can look at the relation in ordered pair format.
If any x is repeated, then it will not be a function.
{(1,5),(1,7),(2,5),(3,6)}
If all x values are different, it will be a function.
{(2,4),(3,5),(4,6),(5,8)}

3. Vertical Line Test Used to see if a graph represents a function.
Not A Function
Function
The vertical line can only go through one point on the graph of a function, otherwise the graph is not a function.

4. Functions Function notation f(x) or g(x) of h(x)...
y = 2x + 7 becomes f(x) = 2x + 7 in function notation. (In other words, the function is using the variable x.)
Given f(x) = 2x + 7
Find f(3) **Hint – plug 3 in the place of x.
f(3) = 2(3) + 7 =
= 13

5. Given g(x) = 3x + 4 and f(x) = x2 + 2
Find g(-2).
g(-2) = 3x + 4
= 3(-2) + 4 =
= -2
Find f(a)
f(a) = a2 + 2
Find f(3) + 4
f(3) + 4 = =
= 15

6. Given g(x) = 3x + 4 and f(x) = x2 + 2
Find 3[g(4)]
3[3(4) + 4]
3[12 + 4]
3(16) 48
Find f(2) + g(5)
(5) + 4
21 + 4 25

7. Try these on your own page 152 #1 - 12
1. Yes
2. No
3. No
4. Yes
5. No
6. Yes
7. 3
8. 4c – 5
9. 4x + 15
10. 2
11. t2 – 3
12. 9n2 + 1

8. Homework #21
p , (even), 43-48, 54, 55