2. What is a function?
Machine with an input and output
Output based on input
Every input has only one output
3. Displaying Functions as Tables
Given specific X-value
Plug X-value into machine
Y-value based on X and machine
Put in table.
X Y
Ex: 1 2
Y=x+1 2 3
3 4
4 5
4. Displaying Functions as graphs
Go left or right X-value
From there
Up and down y-value
Connect dots
Ex: X Y
1 2
2 3
3 4
4 5
5. Domain & Range
Domain: set of all x’s in the function
Range: set of all y’s in the function
Ex:
Domain: (-∞, ∞)
Range (-∞, ∞)
6. Is this a function?
X Y X Y
2 3 2 3
4 3 2 4
5 2 3 6
7 8 4 7
This is a function THIS IS NOT A
FUNCTION
7. Is this a function?
This is a function
This is a function
THIS IS NOT A FUNCTION
8. Zeros of a function
When the function equals zero
X+1=0
●
Zero when x=-1
When line cross x-axis
Ex:
●
Line crosses at -1
