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2-1 QUADRATIC FUNCTION Chapter 2

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Page 1: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

2-1 QUADRATIC FUNCTIONChapter 2

Page 2: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

WHAT IS A POLYNOMIAL FUNCTION?

A polynomial function has the form

where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one or more monomials with real coefficients and nonnegative integer exponents. The degree of the polynomial function is the highest value for n where an is not equal to 0. Polynomial functions of only one term are called monomials or power functions.

Page 3: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

CLASSIFICATION OF POLYNOMIALS

Polynomials are classify based on the leading exponent and that leading exponent is what we called degree.

has degree 0 and is called constant function.

has degree 1 and is called linear function

has degree 2 and is called quadratic function

Page 4: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

QUADRATIC FUNCTION

quadratic function is a function of the form

where ,a, b and c and are real numbers and not equal to zero. The graph of the quadratic function is called a parabola. It is a "U" shaped curve that may open up or down depending on the sign of coefficient a .

Page 5: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

EXAMPLES OF QUADRATIC FUNCTIONS Lets just graph the examples :

Page 6: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

PROPERTIES OF THE QUADRATIC FUNCTION

Page 7: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

THE STANDARD FORM OF A QUADRATIC FUNCTION

Any quadratic function can be written in the standard form

where h and k and are given in terms of coefficients a, b and c .

The graph of f is a parabola whose axis is the vertical line x=h and whose vertex is the point(h ,k ). When a>o, the parabola opens upward, and when a<0, the parabola opens downward.

Page 8: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

IDENTIFYING THE VERTEX OF A QUADRATIC FUNCTION

Write the quadratic function given by in standard form and find the vertex of the graph.

Page 9: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

IDENTIFYING THE VERTEX OF A QUADRATIC FUNCTION

Write the quadratic function given by in standard form and find the vertex of the graph.

Page 10: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

STUDENT GUIDED PRACTICE

Do problems 23-25 from book page 96

Page 11: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

IDENTIFYING THE X-INTERCEPTS OF THE QUADRATIC FUNCTION

The intercepts of the graph of a quadratic function given by

are the real solutions, if they exist, of the quadratic equation

Page 12: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

EXAMPLE OF FINDING THE X-INTERCEPTS Find the x intercepts for the graph of

each function given below a) b) )

Page 13: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

STUDENT GUIDED PRACTICE

Do problems 49 and 51 from book page 97

Page 14: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

MAXIMUM AND MINIMUM

What is the minimum value? When the parabola opens upward , the

y-value of the vertex is the minimum value.

What is the maximum value? When the parabola opens downward

the y-value of the vertex is the maximum value.

Page 15: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one
Page 16: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

FINDING THE MINIMUM AND MAXIMUM Find the minimum or maximum value of

f(x) = –3x2 + 2x – 4.

Solution:

Step 1 Determine whether the function has minimum or maximum value.

Because a is negative, the graph opens downward and has a maximum value.

Step 2 Find the x-value of the vertex.

Page 17: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

CONTINUE

Step 3 Then find the y-value of the vertex,

The maximum value is -11/3

Page 18: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

STUDENT GUIDED PRACTICE

Find the minimum or maximum value of f(x) = 6x2 + 5x – 4.

Page 19: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

STUDENT GUIDED PRACTICE

Find the maxima or minima from the following function

Page 20: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

HOMEWORK

Do problems 24-27 and 33 and 36 from page 96

Page 21: Chapter 2.  A polynomial function has the form  where are real numbers and n is a nonnegative integer. In other words, a polynomial is the sum of one

CLOSURE

Today we learned about quadratic equations

Next time we are going to continue with 2.3