Download SWBAT determine if a graph is a function, and the domain and range

SWBAT determine if a graph is a
function, and the domain and range
On white board:
Function Definition
• There exists only ONE ‘y’ value for a single ‘x’
– Two different ‘X’ can have the same ‘Y’ Value
Functions:
X: { 1, 2, 3, 4, 5}
Y: { 3, 2, 1, 3, 8}
Not Function
X: { 1, 2, 1, 3, 4}
Y: { 2, 3, 7, 8, 6}
Functions as a Dance Invite
Boys are X
Girls are Y
Multiple boys can ask a girl to a dance:
Jake, Brian, & Steve invited Megan to homecoming:
 Function
A boy cannot ask multiple girls to the dance (the
girls will talk and none will go with him)
Tom asks Laura, Stephanie, & Kelly  Not a
function
Function of a graph
• Vertical Line Test!!!!!!
– Imagine vertical lines pass through the grid.
– If lines touch graph in two places, it fails and is not
a function.
Homework
• PG 136 4A and pg 139 4B #1-2 All
SWBAT use interval notation to
describe the domain and range of
functions and non functions
Solve each Variable:
x + 2y - 3z + 4w = 12
2x + 2y - 2z + 3w = 10
0 + y + z + 0 = -1
x - y + z - 2w = -4
Interval Notation
• [ or ] includes a point just like a filled in dot
on a graph
• ( or ) is used to describe up to that point just
like an open dot on a graph
– Also used to describe + or - negative infinity
• Because we never “Get To” infinity
-3 < x < 9 gets written as (-3, 9)
Domain
Function: X: { 1, 3, 6, 9, 10}
Y: { -1, -4, -4, -10, -13}
• Possible ‘X’ values of a function
– If specific points, list exact numbers.
Domain: { 1, 3, 6, 9, 10}
– If continues, give a range of values
Ex: [-1, 10)
Range:
Function: X: { 1, 3, 6, 9, 10}
Y: { -1, -4, -4, -10, -13}
• Possible Y values from a graph or function
• If specific points, list exact numbers.
– Range: { -1, -4, -10, -13}
• If continuous graph, give interval
Range: (3, 19]