10.2 Quadratic Functions:
Objectives:
1. Find a vertex
2. Graph quadratic functions Warm­Up
Evaluate the expressions for ­b
2a
a = ­4 and b = 5
a = 9 and b = ­8
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Parabola
Line of symmetry
Roots
Vertex
The vertex is the maximum or minimum of our parabola. The axis of symmetry goes through our vertex. We can find a vertex just by looking at the equation!
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1. Example: Finding a vertex ax2 + bx + c
y = 2x2 + 4x ­ 3
Find the line of symmetry to find the vertex
x = ­b
2a
Use the x­coordinate to find the vertex!
2. Example: Finding a vertex ax2 + bx + c
y = 2x2 + 4
Find the line of symmetry to find the vertex
x = ­b
2a
Use the x­coordinate to find the vertex!
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3. Example: Finding a vertex ax2 + bx + c
y = x2 ­8x ­ 9
Find the line of symmetry to find the vertex
x = ­b
2a
Use the x­coordinate to find the vertex!
4. Example: Graphing without a t­table
y = ­3x2 + 6x + 5
ax2 + bx + c
Find the vertex
Find two other points on the graph
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5. Example: Graphing without a t­table
y = x2 ­ 6x + 9
ax2 + bx + c
Find the vertex
Find two other points on the graph
6. Example: Graphing without a t­table
y = 2x2 ­6x
ax2 + bx + c
Find the vertex
Find two other points on the graph
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7. Example: Graphing without a t­table
ax2 + bx + c
y = ­x2 + 4x ­ 4
Find the vertex
Find two other points on the graph
Homework #36:
Pg 560 #1­14
MUST BE ON GRAPH PAPER!!!!
Webcode:
ate­1002
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