Match the graph to its equation.
y = x2
y = ­ 1/5x2
y = 3x2
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RECAP:
Standard Form of a Quadratic Equation:
Shape of the graph is called:
Line that divides a parabola is called:
Each parabola has a _________________ or _________________ point called the
____________________.
"a" tells us two things
1. If a is positive, then ___________. If a is negative, then _____________.
2. a tells the ________________ of the parabola.
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HW Solutions p. 321 # 1 ­ 12, 17 ­ 20, 29 ­ 39
1. a=1,b=2,c=4
17. widest to narrowest: y = x2, y = 3x2, y = 7x2
2. a=2,b=0,c=0
18. widest to narrowest: y = 1/3x2, y = x2, y = 4x2
3. a=­1,b=­3,c=­9
19. widest to narrowest: y = ­2/3x2, y =­2x2, y = ­4x2
4. a=­2,b=0,c=5
20. widest to narrowest: y = ­1/4x2, y = ­1/2x2, y = 5x2
5. up; min
6. up; min
7. down, max
8. down, max
29. y = 2x2: narrower
30. y = ­x2: flip over x­axis
31. y = 1.5x2: narrower
32. y = 1/2x2: wider
34. D
35. E
36. B
37. F
38. A
39. C
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9. y = 1/2x2
10. y = 1.5x2
4
11. y = ­4x2
12. y = ­1/3x2
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7-2 Graphing Simple Quadratic Functions
Objective: Graph quadratic functions of the form y = ax2 + c.
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Graph each function.
What is a, b, and c for each?
What is different about these three graphs?
y = x2
y = x2 + 2
y = x2 ­ 3
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Conclusions about c
If c is positive the graph shifts ____________ from the
x-axis.
If c is negative the graph shifts ___________ from the
x-axis.
c is also the _______________ of the quadratic function.
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What would be different about the graphs
y = 1/2x2 and y = 1/2x2 - 4 ?
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Graph y = 2x2 + 1
opens ______
y­int ________
min or max______
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Graph y = -x2 + 3
opens ______
y­int ________
min or max_____
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1. most narrow?
y = -10x2 + 4.5
2. opens upward?
y = -3x2 + 4
3. y-intercept is below x-axis?
y = -2x2 - 1
4. widest?
5. maximum point?
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BB # 3
HW # 69
Due 3/4
p. 325-26 # 1-9,18,19,21-32
**Need graph paper for 6-9 !!
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