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Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least degree with given roots. Identify all of the roots of a polynomial equation. Objectives

Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

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Page 1: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least degree with given roots.

Identify all of the roots of a polynomial equation.

Objectives

Page 2: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

You have learned several important properties about real roots of polynomial equations.

You can use this information to write polynomial function when given in zeros.

Page 3: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

Write the simplest polynomial function with the given zeros.

Check It Out! Example 1a

–2, 2, 4

Page 4: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

Write the simplest polynomial function with the given zeros.

Check It Out! Example 1b

0, , 32 3

Page 5: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

Notice that the degree of the function in Example 1 is the same as the number of zeros. This is true for all polynomial functions. However, all of the zeros are not necessarily real zeros. Polynomials functions, like quadratic functions, may have complex zeros that are not real numbers.

Page 6: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

Using this theorem, you can write any polynomial function in factor form.

To find all roots of a polynomial equation, you can use a combination of the Rational Root Theorem, the Irrational Root Theorem, and methods for finding complex roots, such as the quadratic formula.

Page 7: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

Solve x4 + 4x3 – x2 +16x – 20 = 0 by finding all roots.

Check It Out! Example 2

Page 8: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

Find the real roots at or near –5 and 1.

Step 2 Graph y = x4 + 4x3 – x2 + 16x – 20 to find the real roots.

Check It Out! Example 2 Continued

Page 9: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

Step 3 Test the possible real roots.

Check It Out! Example 2 Continued

Page 10: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

Write the simplest function with zeros 2i, , and 3.

Step 1 Identify all roots.

Check It Out! Example 3

1+ 2

Page 11: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

A grain silo is in the shape of a cylinder with a hemisphere top. The cylinder is 20 feet tall. The volume of the silo is 2106 cubic feet. Find the radius of the silo.

List the important information:

• The cylinder is 20 feet tall.

• The height of the hemisphere is x.

• The volume of the silo is 2106 cubic feet.

11 Understand the ProblemThe cylinder and the hemisphere will have the same radius x. The answer will be the value of x.

Check It Out! Example 4

Page 12: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

22 Make a Plan

Write an equation to represent the volume of the body of the silo.

V = Vhemisphere + Vcylinder

Page 13: Holt McDougal Algebra 2 3-6 Fundamental Theorem of Algebra Use the Fundamental Theorem of Algebra and its corollary to write a polynomial equation of least

Holt McDougal Algebra 2

3-6 Fundamental Theorem of Algebra

Solve33