1. 4.2
Functions

2. Students are expected to:
* Identify, generalize, and apply patterns.
* Use interpolation, extrapolation, and equations to predict and solve problems.
* Gather data, plot the data using appropriate scales,
* Create and analyse scatter plots using appropriate technology.
* Sketch graphs from words, tables, and collected data.
Determine the equation of a line using the slope and
y-intercept.
* Solve problems by modeling real-world phenomena.

3. Functions
A function is a relation in which each element of the domain is paired with exactly one element of the range. Another way of saying it is that there is one and only one output (y) with each input (x).
f(x) y x

4. Function Notation
Input
Name of Function
Output

5. Determine whether each relation is a function.
1. {(2, 3), (3, 0), (5, 2), (4, 3)}
YES, every domain is different!
f(x) 2 3
f(x) 3
f(x) 5 2
f(x) 4 3

6. Determine whether the relation is a function.
2. {(4, 1), (5, 2), (5, 3), (6, 6), (1, 9)}
f(x) 4 1
f(x) 5 2
NO, 5 is paired with 2 numbers!
f(x) 5 3
f(x) 6
f(x) 1 9

7. Is this relation a function? {(1,3), (2,3), (3,3)}
Yes No
Answer Now

8. Vertical Line Test (pencil test)
If any vertical line passes through more than one point of the graph, then that relation is not a function.
Are these functions?
FUNCTION!
FUNCTION!
NOPE!

9. Vertical Line Test
FUNCTION!
NO!
NO WAY!
FUNCTION!

10. Is this a graph of a function?
Yes No
Answer Now

11. 3(3)-2 3 7 -2 -8 3(-2)-2 1) f (3) = 7 2) f (-2) = -8
Given f(x) = 3x - 2, find:
1) f (3)
2) f (-2)
= 7
3(3)-2 3 7
= -8
3(-2)-2 -2 -8

12. Given h (z) = z2 - 4z + 9, find h (-3)
(-3)2-4(-3)+9 -3 30
h(-3) = 30

13. Given g(x) = x2 – 2, find g(4) 2 6 14 18
Answer Now

14. Given f(x) = 2x + 1, find -4[f(3) – f(1)]
-40
-16 -8 4
Answer Now

15. Let’s Do Some Practice!
CYU # 8-10 Homework : CYU 11-16, 20-23