2.2 - Quadratic Functions in Intercept & Standard Forms...Obj: Idenify properties of quads in...

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2.2 Quadratic Functions in Intercept & Standard Forms September 21, 2018 Ex 2: Graph the function. Label the roots(xint), vertex, and axis of symmetry. f(x) = 1/4(x 6)(x 2) Roots: Axis of Symmetry: Vertex: Domain: ____________ Range: _____________

Transcript of 2.2 - Quadratic Functions in Intercept & Standard Forms...Obj: Idenify properties of quads in...

Page 1: 2.2 - Quadratic Functions in Intercept & Standard Forms...Obj: Idenify properties of quads in standard form and graph. 2.2 Quadratic Functions in Intercept & Standard Forms September

2.2 ­ Quadratic Functions in Intercept & Standard Forms September 21, 2018

Ex 2:  Graph the function. Label the roots(x­int), vertex, and axis of symmetry.

f(x) = ­1/4(x ­ 6)(x ­ 2)Roots:

Axis of Symmetry:

Vertex:

Domain: ____________

Range: _____________

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2.2 ­ Quadratic Functions in Intercept & Standard Forms September 21, 2018

Ex 3:  Tell whether the graph opens up or down, the identify the roots(x­int) for each functions.

a)   f(x) = ­(x + 8)(x ­ 4)

b)  y = ­2x(x + 7)

c)  g(x) = 2/3(x + 3)2 

HINT: For roots, just set each expression containing x equal to zero and solve.

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2.2 ­ Quadratic Functions in Intercept & Standard Forms September 21, 2018

Minimum or Maximum value: the y­value of the vertex.

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2.2 ­ Quadratic Functions in Intercept & Standard Forms September 21, 2018

Ex 4:  Find the min/max value for each function.

a)   f(x) = ­(x + 8)(x ­ 4)

b)  y = 0.4(x + 3)2

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2.2 ­ Quadratic Functions in Intercept & Standard Forms September 21, 2018

2.2 - Quadratic Functions in Standard Form• Standard Form and Properties:• f(x) = ax2 + bx + c where a 0• Gives us the y­intercept @ (0, c)• Can find an axis of symmetry by calculating:

• The graph is:• narrower when |a| > 1• wider when |a| < 1

Obj: Idenify properties of quads in standard form and graph.

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2.2 ­ Quadratic Functions in Intercept & Standard Forms September 21, 2018

Characteristics of  :If a>0: graph opens ____.

If a<0: graph opens ____.

Axis of symmetry:

Vertex:

y­intercept is c.

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2.2 ­ Quadratic Functions in Intercept & Standard Forms September 21, 2018

Ex 1: Graph y = ­3x2 ­ 12x + 1

x

y

5) Domain:

6) Range:

Does this graph open up or down?

1)  Axis of symmetry:

2) Find the vertex:

3) Find the y­intercept:

4) Reflect the y­intercept.

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2.2 ­ Quadratic Functions in Intercept & Standard Forms September 21, 2018

Ex 2: Graph h(x) = 1/3x2 + 2x ­ 1

x

y

5) Domain:

6) Range:

Does this graph open up or down?

1)  Axis of symmetry:

2) Find the vertex:

3) Find the y­intercept:

4) Reflect the y­intercept.

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2.2 ­ Quadratic Functions in Intercept & Standard Forms September 21, 2018

Ex 3: Tell whether the function has a minimum or maximum value. Then find that value.

y = ­3x2 + x ­ 2

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2.2 ­ Quadratic Functions in Intercept & Standard Forms September 21, 2018

You Try! ANSWERS1.  2. 

(a) Opens up or down?

(b) Axis of symmetry:

(c) Vertex:

(d) Minimum or Maximum?

(e) Min/Max value:

(a) Opens up or down?

(b) Axis of symmetry:

(c) Vertex:

(d) Minimum or Maximum?

(e) Min/Max value:

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2.2 ­ Quadratic Functions in Intercept & Standard Forms September 21, 2018

What does each form give us?

1.  Vertex form:  y = a(x ­ h)2 + kGives us the:

2.  Intercept form:  y = a(x ­ p)(x ­ q)Gives us the:

3. Standard form:  y = ax2 + bx + cGives us the:

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2.2 ­ Quadratic Functions in Intercept & Standard Forms September 21, 2018

2.2 Homework MUST BE DONE ON A SEPARATE SHEET OF PAPER ­ NO EXCEPTIONS!

DUE MONDAY 9/24

Graph the function. Label the vertex and axis of symmetry.

1.  f(x) = ­4(x ­ 2)2 + 4 2.  y = 1/2(x ­ 3)2

Graph the function. Label the roots, vertex, and axis of symmetry.

3.  h(x) = (x + 2)(x ­ 6) 4.  f(x) = 2(x ­ 5)(x ­ 1)

Graph the function. Label the y­intercept and write the domain and range.

5.  f(x) = ­x2 ­ 6x + 3 6.  y = 6x2 ­ 5

Calculate the axis of symmetry for each function, and give the min/max value (example: max @ y = 18).

7.  g(x) = ­(x + 5)(x ­ 3) 8.  y = ­2x2 ­ x + 7 9.  c(x) = 0.75(x ­ 8)2

Identify the roots for each function.

10.  y = ­1/4(x + 2)(x ­ 2) 11.  h(x) = 4(x ­ 9)2 12.  f(x) = ­4x(x + 7)