Precalculus Study Guide
Copyright Maplesoft, a division of Waterloo Maple Inc., 2024
Chapter 3: Graphing Polynomial Functions
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Introduction
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After straight lines, the simplest functions to study are the real polynomials, the general form of which is
where the real numbers , are the coefficients, with called the leading coefficient. Real polynomials are those whose coefficients are real numbers. The integer is the degree of the polynomial.
If , the polynomial function, which then has the form
is called quadratic, whereas if , the polynomial function, which then has the form
is called cubic.
If , then is called a zero of the polynomial, and is then a factor of the polynomial. For each zero , there is a corresponding factor , so that the factored form of the polynomial is
Hence, given the zeros of a polynomial, it is possible to reconstruct the polynomial itself.
(The fundamental theorem of algebra states that every polynomial of degree has exactly zeros, although they may not all be distinct - there can be repeated zeros.)
If the polynomial function is graphed, the real zeros are the -intercepts.
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Chapter Glossary
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The following terms in Chapter 3 are linked to the Maple Math Dictionary.
coefficient
complete the square
complex conjugate
coordinate
cubic
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factor
fundamental theorem of algebra
integer
intercept
leading coefficient
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long division
monic polynomial
parabola
polynomial
quadratic formula
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quartic
real number
synthetic division
tangent
zero
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Typical Problems
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For the polynomial functions given in Problems 1 - 3, sketch a graph and determine both the - and -intercepts. Since the -intercepts are the zeros of the polynomials, they can be found approximately from the graph, or exactly, by factoring the polynomial over the real numbers.
3.1. (a)
(b)
(c)
3.2. (a)
(b)
(c)
(d)
3.3. (a)
(b)
3.4. For each of the following, find the real monic polynomial of least degree having the given numbers as its zeros. (A real polynomial is one whose coefficients are real. A monic polynomial has leading coefficient 1, that is, the coefficient of the term with the highest power is 1.)
(a)
(b) { + , 1 }
(c) { 1, 3, 1 + }
(d)
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Maple Initializations
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Before accessing the Maple version of the solutions to the typical problems stated above, initialize Maple by pressing the button provided on the right.
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Solutions
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Problem 3.1
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3.1 - Mathematical Solution
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3.1 (a) - Mathematical Solution
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For the function , the -intercept is found to be , and the -intercepts are found from the quadratic formula to be
= 2
and
=
Moreover, factors to the product .
Since the function is a quadratic polynomial, its graph is that of a parabola, opening upward. The standard form of this parabola would be
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Figure 3.1.1 Graph of
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obtained by completing the square in . Thus, the coordinates of the vertex of the parabola are.
From this information, Figure 3.1.1, a graph of the function, can be drawn.
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3.1 (b) - Mathematical Solution
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For the function , the -intercept is found to be , and the -intercepts are found from the quadratic formula to be
= 1
and
=
Moreover, factors to the product .
Since the function is a quadratic polynomial, its graph is that of a parabola, opening upward. The standard form of this parabola would be
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Figure 3.1.2 Graph of
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obtained by completing the square in . Thus, the coordinates of the vertex of the parabola are.
From this information, Figure 3.1.2, a graph of the function, can be drawn.
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3.1 (c) - Mathematical Solution
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For the function , the -intercept is found to be , and the -intercepts are found from the quadratic formula to be
=
and
=
Moreover, does not factor over the real numbers.
Since the function is a quadratic polynomial, its graph is
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Figure 3.1.3 Graph of
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that of a parabola, opening upward. The standard form of this parabola would be
obtained by completing the square in . Thus, the coordinates of the vertex of the parabola are.
From this information, Figure 3.1.3, a graph of the function, can be drawn.
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3.1 - Maplet Solution
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3.1 (a) - Maplet Solution
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A graph of the polynomial function , along with its intercepts, can be obtained with
Polynomial Tutor #1
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Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail image in Figure 3.1.4.
To use this tutor, enter the coefficients of the polynomial in the appropriate boxes. Blanks will be interpreted as the number zero (0).
The Display Function button will display the polynomial entered, while the buttons labeled Graph, -intercepts, and -intercept will generate the corresponding results.
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Figure 3.1.4 Thumbnail image of Polynomial Tutor #1
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To launch Polynomial Tutor #1, click the following link:
Polynomial Tutor #1
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3.1 (b) - Maplet Solution
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A graph of the polynomial function , along with its intercepts, can be obtained with
Polynomial Tutor #1
.
Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail image in Figure 3.1.5.
To use this tutor, enter the coefficients of the polynomial in the appropriate boxes. Blanks will be interpreted as the number zero (0).
The Display Function button will display the polynomial entered, while the buttons labeled Graph, -intercepts, and -intercept will generate the corresponding results.
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Figure 3.1.5 Thumbnail image of Polynomial Tutor #1
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Since the -intercepts are the zeros of the polynomial, if a zero is repeated, it will appear the appropriate number of times in the list of -intercepts.
To launch Polynomial Tutor #1, click the following link:
Polynomial Tutor #1
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3.1 (c) - Maplet Solution
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A graph of the polynomial function , along with its intercepts, can be obtained with
Polynomial Tutor #1
.
Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail image in Figure 3.1.6.
To use this tutor, enter the coefficients of the polynomial in the appropriate boxes. Blanks will be interpreted as the number zero (0).
The Display Function button will display the polynomial entered, while the buttons labeled Graph, -intercepts, and -intercept will generate the corresponding results.
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Figure 3.1.6 Thumbnail image of Polynomial Tutor #1
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If the polynomial has no real zeros, its graph will not cross the -axis. Hence, there will be no -intercepts returned.
To launch Polynomial Tutor #1, click the following link:
Polynomial Tutor #1
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3.1 - Interactive Solution
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3.1 (a) - Interactive Solution
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Context Panel: Assign to a Name≻
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Obtain Figure 3.1.1
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Type and press the Enter key.
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Context Panel: Plots≻Plot Builder
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Obtain -intercept(s)
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Type and press the Enter key.
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Context Panel: Solve≻Solve
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Obtain the -intercept
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Type and press the Enter key.
Context Panel: Evaluate at a Point≻
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3.1 (b) - Interactive Solution
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Context Panel: Assign to a Name≻
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Obtain Figure 3.1.2
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Type and press the Enter key.
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Context Panel: Plots≻Plot Builder
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Obtain -intercept(s)
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Type and press the Enter key.
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Context Panel: Solve≻Solve
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Obtain the -intercept
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Type and press the Enter key.
Context Panel: Evaluate at a Point≻
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3.1 (c) - Interactive Solution
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Context Panel: Assign to a Name≻
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Obtain Figure 3.1.3
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Type and press the Enter key.
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Context Panel: Plots≻Plot Builder
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Obtain -intercept(s)
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Type and press the Enter key.
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Context Panel: Solve≻Solve
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Obtain the -intercept
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Type and press the Enter key.
Context Panel: Evaluate at a Point≻
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3.1 - Programmatic Solution
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3.1 (a) - Programmatic Solution
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Enter the polynomial.
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Graph the polynomial as per Figure 3.1.1.
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Obtain the -intercepts.
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Obtain the -intercept.
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3.1 (b) - Programmatic Solution
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Enter the polynomial.
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Graph the polynomial as per Figure 3.1.1.
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Obtain the -intercepts.
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Obtain the -intercept.
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3.1 (c) - Programmatic Solution
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Enter the polynomial.
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Graph the polynomial as per Figure 3.1.1.
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Obtain the -intercepts.
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Obtain the -intercept.
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Problem 3.2
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3.2 - Mathematical Solution
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3.2 (a) - Mathematical Solution
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The polynomial has for its -intercept, and for its -intercept.
The graph is a translation to the left, by one unit, of the graph of . Hence, the graph of can be sketched, as shown in Figure 3.2.1.
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Figure 3.2.1 Graph of
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3.2 (b) - Mathematical Solution
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The polynomial has -intercept , and -intercept . This is found by searching for integer zeros, computing the values of .
Although there are formulas expressing the zeros of a cubic in terms of its coefficients, they are very cumbersome to apply. That is the only zero of is determined by dividing out the factor , leaving the quadratic polynomial whose zeros are the complex conjugate pair 3 + .
The division of by the factor can be done by synthetic division, the tableau for which appears in Table 3.2.1
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Figure 3.2.2 Graph of
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The final zero is the remainder, so the factor divides evenly. The coefficients of the depressed polynomial are the numbers to the left of the final zero in the bottom row of the tableau.
The zeros of the depressed polynomial are found with the quadratic formula, and they are
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1 4 10 [-1
6
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1 10 0
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Table 3.2.1 Synthetic division
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= =
= =
Without a plotting device such as a calculator or computer, a graph can only be drawn from computed values such as those appearing in Table 3.2.2.
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3.0
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Table 3.2.2 Values of the function
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The graph of in Figure 3.2.2 was obtained with Maple. Drawing such a graph with just a pencil and paper is a daunting task.
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3.2 (c) - Mathematical Solution
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The polynomial has -intercept and an -intercept at . This is found by searching for zeros amongst the integers, and fortunately, this zero is an integer. Thus, is a factor of the polynomial.
The companion factor is found by dividing by . This division can be done by long division or by the synthetic division shown in the tableau in Table 3.2.3.
The final zero in the last row of the tableau is the remainder, so the factor divides evenly. The coefficients of the depressed polynomial are the numbers to the left of the final zero in the bottom row of the tableau.
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Figure 3.2.3 Graph of
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The zeros of the depressed polynomial are found with the quadratic formula or by noticing that . Thus, the remaining zeros are 1 and again 1, so that is a double zero. There are two -intercepts, namely, and , the latter being a double zero of the polynomial.
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1 0 2 [
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1 1 0
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Table 3.2.3 Synthetic division
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From this information, a sketch of can be drawn. The graph in Figure 3.2.3 was obtained in Maple.
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3.2 (d) - Mathematical Solution
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The polynomial has -intercept and an -intercept at . This is found by searching for zeros amongst the integers, and fortunately, this zero is an integer. Thus, is a factor of the polynomial.
The companion factor is found by dividing by . This division can be done by long division or by the synthetic division shown in the tableau in Table 3.2.4.
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Figure 3.2.4 Graph of
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The final zero in the last row of the tableau is the remainder, so the factor divides evenly. The coefficients of the depressed polynomial are the numbers to the left of the final zero in the bottom row of the tableau.
The zeros of the depressed polynomial are found with the quadratic formula, and they are
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1 2 [
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1 2 0
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Table 3.2.4 Synthetic division
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= =
= =
Thus, the remaining -intercepts are and , so a sketch of could now be drawn. The graph in Figure 3.2.4 was obtained in Maple.
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3.2 - Maplet Solution
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3.2 (a) - Maplet Solution
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A graph of the polynomial function , along with its intercepts, can be obtained with
Polynomial Tutor #1
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Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail image in Figure 3.2.5.
To use this tutor, enter the coefficients of the polynomial in the appropriate boxes. Blanks will be interpreted as the number zero (0).
The Display Function button will display the polynomial entered, while the buttons labeled Graph, -intercepts, and -intercept will generate the corresponding results.
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Figure 3.2.5 Thumbnail image of Polynomial Tutor #1
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Since the -intercepts are the zeros of the polynomial, if a zero is repeated, it will appear the appropriate number of times in the list of -intercepts.
To launch Polynomial Tutor #1, click the following link:
Polynomial Tutor #1
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3.2 (b) - Maplet Solution
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A graph of the polynomial function , along with its intercepts, can be obtained with
Polynomial Tutor #1
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Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail in Figure 3.2.6.
To use this tutor, enter the coefficients of the polynomial in the appropriate boxes. Blanks will be interpreted as the number zero (0).
The Display Function button will display the polynomial entered, while the buttons labeled Graph, -intercepts, and -intercept will generate the corresponding results.
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Figure 3.2.6 Thumbnail image of Polynomial Tutor #1
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To launch Polynomial Tutor #1, click the following link:
Polynomial Tutor #1
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3.2 (c) - Maplet Solution
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A graph of the polynomial function , along with its intercepts, can be obtained with
Polynomial Tutor #1
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Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail image in Figure 3.2.7.
To use this tutor, enter the coefficients of the polynomial in the appropriate boxes. Blanks will be interpreted as the number zero (0).
The Display Function button will display the polynomial entered, while the buttons labeled Graph, -intercepts, and -intercept will generate the corresponding results.
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Figure 3.2.7 Thumbnail image of Polynomial Tutor #1
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Since the -intercepts are the zeros of the polynomial, if a zero is repeated, it will appear the appropriate number of times in the list of -intercepts.
To launch Polynomial Tutor #1, click the following link:
Polynomial Tutor #1
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3.2 (d) - Maplet Solution
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A graph of the polynomial function , along with its intercepts, can be obtained with
Polynomial Tutor #1
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Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail image in Figure 3.2.8.
To use this tutor, enter the coefficients of the polynomial in the appropriate boxes. Blanks will be interpreted as the number zero (0).
The Display Function button will display the polynomial entered, while the buttons labeled Graph, -intercepts, and -intercept will generate the corresponding results.
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Figure 3.2.8 Thumbnail image of Polynomial Tutor #1
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To launch Polynomial Tutor #1, click the following link:
Polynomial Tutor #1
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3.2 - Interactive Solution
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3.2 (a) - Interactive Solution
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Context Panel: Assign to a Name≻
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Obtain Figure 3.2.1
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Type and press the Enter key.
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Context Panel: Plots≻Plot Builder
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Obtain -intercept(s)
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Type and press the Enter key.
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Context Panel: Solve≻Solve
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Obtain the -intercept
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Type and press the Enter key.
Context Panel: Evaluate at a Point≻
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3.2 (b) - Interactive Solution
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Context Panel: Assign to a Name≻
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Obtain Figure 3.2.2
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Type and press the Enter key.
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Context Panel: Plots≻Plot Builder
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Obtain -intercept(s)
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Type and press the Enter key.
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Context Panel: Solve≻Numerically Solve
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Obtain the -intercept
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Type and press the Enter key.
Context Panel: Evaluate at a Point≻
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3.2 (c) - Interactive Solution
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Context Panel: Assign to a Name≻
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Obtain Figure 3.2.3
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Type and press the Enter key.
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Context Panel: Plots≻Plot Builder
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Obtain -intercept(s)
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Type and press the Enter key.
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Context Panel: Solve≻Solve
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Obtain the -intercept
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Type and press the Enter key.
Context Panel: Evaluate at a Point≻
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3.2 (d) - Interactive Solution
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Context Panel: Assign to a Name≻
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Obtain Figure 3.2.4
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Type and press the Enter key.
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Context Panel: Plots≻Plot Builder
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Obtain -intercept(s)
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Type and press the Enter key.
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Context Panel: Solve≻Solve
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Obtain the -intercept
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Type and press the Enter key.
Context Panel: Evaluate at a Point≻
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3.2 - Programmatic Solution
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3.2 (a) - Programmatic Solution
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Enter the polynomial.
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Graph the polynomial as per Figure 3.2.1.
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Obtain the -intercepts.
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Obtain the -intercept.
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3.2 (b) - Programmatic Solution
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Enter the polynomial.
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Graph the polynomial as per Figure 3.2.2
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Obtain the -intercepts.
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Obtain the -intercept.
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3.2 (c) - Programmatic Solution
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Enter the polynomial.
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Graph the polynomial as per Figure 3.2.3
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Obtain the -intercepts.
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Obtain the -intercept.
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3.2 (d) - Programmatic Solution
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Enter the polynomial.
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Graph the polynomial as per Figure 3.2.4
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Obtain the -intercepts.
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Obtain the -intercept.
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Problem 3.3
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3.3 - Mathematical Solution
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3.3 (a) - Mathematical Solution
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The polynomial has for its -intercept, and for one of its -intercepts. This intercept is found by searching amongst the integers for zeros of the polynomial. Since is a zero, the factor divides the polynomial evenly. The companion factor is found by either long division or synthetic division. The tableau in Table 3.3.1 implements synthetic division by the factor .
1 47 26 [ 1
1
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1 36 0
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Table 3.3.1 Synthetic division
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Figure 3.3.1 Graph of
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The companion factor, the "depressed polynomial," is , which also has as a zero. Again, this is found by searching through the integers. Once again, the factor can be divided out, this time from the depressed polynomial. The synthetic division tableau for this division appears in Table 3.3.2.
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1 36 [ 1
1 26
______________________
1 0
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Table 3.3.2 Synthetic division
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The new depressed polynomial is , whose zeros can be found by the quadratic formula. These remaining zeros are
=
=
Knowledge of just the -intercept and the double zero at does not yet lead to an unambiguous graph. Even making use of the property of quartics that their graphs will at most resemble the letter "W" still leaves a need for a list of values such as found in Table 3.3.3.
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3.3
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Table 3.3.3 Values of the function
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On the basis of all this information, the sketch of seen in Figure 3.3.1 could now be drawn. (However, Figure 3.3.1 was, in fact, generated by Maple.)
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3.3 (b) - Mathematical Solution
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The polynomial has for its -intercept, and for one of its -intercepts. This intercept is found by searching amongst the integers for zeros of the polynomial. Since is a zero, the factor divides the polynomial evenly. The companion factor is found by either long division or synthetic division. The tableau in Table 3.3.4 implements synthetic division by the factor .
1 75 74 [ 1
1
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1 61 0
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Table 3.3.4 Synthetic division
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Figure 3.3.2 Graph of
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The companion factor, the "depressed polynomial," is , which has as a zero. Again, this is found by searching through the integers. The factor can be divided out from the depressed polynomial. The synthetic division tableau for this division appears in Table 3.3.5.
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1 61 [ 2
2 74
______________________
1 0
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Table 3.3.5 Synthetic division
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The new depressed polynomial is , whose zeros can be found by the quadratic formula. These remaining zeros are
=
=
Knowledge of just the -intercept and the zeros at and does not yet lead to an unambiguous graph. Even making use of the property of quartics that their graphs will at most resemble the letter "W" still leaves a need for a list of values such as the one given in Table 3.3.6.
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210.0
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Table 3.3.6 Values of
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On the basis of all this information, the sketch of seen in Figure 3.3.2 could now be drawn. (However, Figure 3.3.2 was, in fact, generated by Maple.)
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3.3 - Maplet Solution
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3.3 (a) - Maplet Solution
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A graph of the polynomial function , along with its intercepts, can be obtained with
Polynomial Tutor #1
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Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail image in Figure 3.3.3.
To use this tutor, enter the coefficients of the polynomial in the appropriate boxes. Blanks will be interpreted as the number zero (0).
The Display Function button will display the polynomial entered, while the buttons labeled Graph, -intercepts, and -intercept will generate the corresponding results.
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Figure 3.3.3 Thumbnail image of Polynomial Tutor #1
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Since the -intercepts are the zeros of the polynomial, if a zero is repeated, it will appear the appropriate number of times in the list of -intercepts.
To launch Polynomial Tutor #1, click the following link:
Polynomial Tutor #1
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3.3 (b) - Maplet Solution
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A graph of the polynomial function , along with its intercepts, can be obtained with
Polynomial Tutor #1
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Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail image in Figure 3.3.4.
To use this tutor, enter the coefficients of the polynomial in the appropriate boxes. Blanks will be interpreted as the number zero (0).
The Display Function button will display the polynomial entered, while the buttons labeled Graph, -intercepts, and -intercept will generate the corresponding results.
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Figure 3.3.4 Thumbnail image of Polynomial Tutor #1
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To launch Polynomial Tutor #1, click the following link:
Polynomial Tutor #1
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3.3 - Interactive Solution
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3.3 (a) - Interactive Solution
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Context Panel: Assign to a Name≻
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Obtain Figure 3.3.1
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Type and press the Enter key.
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Context Panel: Plots≻Plot Builder
Options≻Range from:
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Obtain -intercept(s)
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Type and press the Enter key.
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Context Panel: Solve≻Solve
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Obtain the -intercept
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Type and press the Enter key.
Context Panel: Evaluate at a Point≻
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3.3 (b) - Interactive Solution
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Context Panel: Assign to a Name≻
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Obtain Figure 3.3.1
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Type and press the Enter key.
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Context Panel: Plots≻Plot Builder
Options≻Range from:
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Obtain -intercept(s)
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Type and press the Enter key.
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Context Panel: Solve≻Solve
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Obtain the -intercept
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Type and press the Enter key.
Context Panel: Evaluate at a Point≻
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3.3 - Programmatic Solution
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3.3 (a) - Programmatic Solution
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Enter the polynomial.
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Graph the polynomial as per Figure 3.2.1.
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Factor the polynomial.
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Obtain the -intercepts.
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Obtain the -intercept.
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3.3 (b) - Programmatic Solution
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Enter the polynomial.
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Graph the polynomial as per Figure 3.2.1.
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Factor the polynomial.
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Obtain the -intercepts.
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Obtain the -intercept.
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Problem 3.4
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3.4 - Mathematical Solution
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3.4 (a) - Mathematical Solution
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If the zeros of a polynomial are and 3, then the polynomial's factored form is
=
and its expanded form is
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3.4 (b) - Mathematical Solution
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If the zeros of a polynomial are + and 1, then the polynomial's factored form is
and its expanded form is
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3.4 (c) - Mathematical Solution
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If the zeros of a polynomial are 1, 3, and + , then the polynomial's factored form is
and its expanded form is
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3.4 (d) - Mathematical Solution
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If the zeros of a polynomial with real coefficients are and , then there must be at least one other zero, namely, , the complex conjugate of the given zero . The factored form of the desired polynomial is then
and its expanded form is
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3.4 - Maplet Solution
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3.4 (a) - Maplet Solution
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The real monic polynomial of least degree having as its zeros can be found with
Polynomial Tutor #2
.
Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail image in Figure 3.4.1.
To use this tutor, enter the zeros in the appropriate box, and press the button labeled Linear factored form. This gives the polynomial as a product of its linear factors, that is, as .
Pressing the button labeled Factored over reals displays the polynomial in terms of factors containing just real coefficients. In this problem where the zeros are all real, the linear factored form and this form are the same.
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Figure 3.4.1 Thumbnail image of Polynomial Tutor #2
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Pressing the button labeled Expanded form displays the polynomial as a sum of "coefficients times powers of ." Colloquially, this is the "multiplied out" form .
As in Polynomial Tutor #1, there are buttons for producing a graph of the required polynomial, and buttons for displaying the intercepts.
To launch Polynomial Tutor #2, click the following link:
Polynomial Tutor #2
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3.4 (b) - Maplet Solution
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The real monic polynomial of least degree having as its zeros can be found with
Polynomial Tutor #2
.
Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail image in Figure 3.4.2.
To use this tutor, enter the zeros in the appropriate box, using I for the complex unit . Each complex zero must be entered separately, since there is no "+" operator in Maple.
Pressing the button labeled Linear factored form gives the polynomial as a product of its linear factors, that is, as
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Figure 3.4.2 Thumbnail image of Polynomial Tutor #2
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Pressing the button labeled Factored over reals displays the polynomial as
a product of factors containing just real coefficients.
Pressing the button labeled Expanded form displays the polynomial as a sum of "coefficients times powers of ." Colloquially, this is the "multiplied out" form .
As in Polynomial Tutor #1, there are buttons for producing a graph of the required polynomial, and buttons for displaying the intercepts.
To launch Polynomial Tutor #2, click the following link:
Polynomial Tutor #2
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3.4 (c) - Maplet Solution
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The real monic polynomial of least degree having as its zeros can be found with
Polynomial Tutor #2
.
Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail image in Figure 3.4.3.
To use this tutor, enter the zeros in the appropriate box, using I for the complex unit . Each complex zero must be entered separately, since there is no "+" operator in Maple.
Pressing the button labeled Linear factored form gives the polynomial as a product of its linear factors, that is, as
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Figure 3.4.3 Thumbnail image of Polynomial Tutor #2
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Pressing the button labeled Factored over reals displays the polynomial as
a product of factors containing just real coefficients.
Pressing the button labeled Expanded form displays the polynomial as a sum of "coefficients times powers of ." Colloquially, this is the "multiplied out" form .
As in Polynomial Tutor #1, there are buttons for producing a graph of the required polynomial, and buttons for displaying the intercepts.
To launch Polynomial Tutor #2, click the following link:
Polynomial Tutor #2
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3.4 (d) - Maplet Solution
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The real monic polynomial of least degree having as its zeros will also have as a zero. Remember, polynomials with real coefficients will have any of its complex zeros appearing as complex conjugate pairs. The required polynomial can be found with
Polynomial Tutor #2
.
Clicking this link will launch the tutor with the solution embedded as shown in the thumbnail image in Figure 3.4.4.
To use this tutor, enter the zeros in the appropriate box, using I for the complex unit . Each complex zero must be entered separately, since there is no "+" operator in Maple.
Pressing the button labeled Linear factored form gives the polynomial as a product of its linear factors, that is, as
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Figure 3.4.4 Thumbnail image of Polynomial Tutor #2
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Pressing the button labeled Factored over reals displays the polynomial as
a product of factors containing just real coefficients.
Pressing the button labeled Expanded form displays the polynomial as a sum of "coefficients times powers of ." Colloquially, this is the "multiplied out" form .
As in Polynomial Tutor #1, there are buttons for producing a graph of the required polynomial, and buttons for displaying the intercepts.
To launch Polynomial Tutor #2, click the following link:
Polynomial Tutor #2
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3.4 - Interactive Solution
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3.4 (a) - Interactive Solution
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•
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Context Panel: Assign to a Name≻
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Context Panel: Assign to a Name≻
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Write the polynomial as a product of linear factors.
Context Panel: Expand
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3.4 (b) - Interactive Solution
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Context Panel: Assign to a Name≻
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Context Panel: Assign to a Name≻
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Context Panel: Assign to a Name≻
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Write the polynomial as a product of linear factors.
Context Panel: Expand
Context Panel: Factor
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3.4 (c) - Interactive Solution
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Context Panel: Assign to a Name≻
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Context Panel: Assign to a Name≻
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Context Panel: Assign to a Name≻
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Context Panel: Assign to a Name≻
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Write the polynomial as a product of linear factors.
Context Panel: Expand
Context Panel: Factor
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3.4 (d) - Interactive Solution
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Context Panel: Assign to a Name≻
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Enter the complex zero.
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Context Panel: Assign to a Name≻
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Enter the third zero, the complex conjugate of .
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Context Panel: Assign to a Name≻
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Write the polynomial as a product of linear factors.
Context Panel: Expand
Context Panel: Factor
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3.4 - Programmatic Solution
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3.4 (a) - Programmatic Solution
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Enter the given zeros, assigning them to the names .
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Write the desired polynomial as a product of linear factors.
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Expand the product of factors.
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3.4 (b) - Programmatic Solution
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Enter the given zeros, assigning them to the names .
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Write the desired polynomial as a product of linear factors.
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Expand the product of factors.
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Factor the polynomial over the reals.
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3.4 (c) - Programmatic Solution
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Enter the given zeros, assigning them to the names .
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Write the desired polynomial as a product of linear factors.
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Expand the product of factors.
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Factor the polynomial over the reals.
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3.4 (d) - Programmatic Solution
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Enter the given zeros, assigning them to the names .
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Write the desired polynomial as a product of linear factors.
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Expand the product of factors.
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Factor the polynomial over the reals.
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Exercises - Chapter 3
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For the quadratic polynomial functions given in Exercises 3.1 - 3.6, sketch a graph and determine both the - and -intercepts. Since the -intercepts are the zeros of the polynomials, they can be found by the quadratic formula.
3.1.
3.2.
3.3.
3.4.
3.5.
3.6.
For the cubic polynomial functions given in Exercises 3.7 - 3.12, sketch a graph and determine both the - and -intercepts. Since the -intercepts are the zeros of the polynomials, they can be found approximately from the graph, or exactly, by factoring the polynomial over the real numbers.
3.7.
3.8.
3.9.
3.10.
3.11.
3.12.
For the quartic polynomial functions given in Exercises 3.13 - 3.18, sketch a graph and determine both the - and -intercepts. Since the -intercepts are the zeros of the polynomials, they can be found approximately from the graph, or exactly, by factoring the polynomial over the real numbers.
3.13.
3.14.
3.15.
3.16.
3.17.
3.18.
In Exercises 3.19 - 3.20, one complex zero of a quartic polynomial whose coefficients are real is given. Find the remaining three zeros. Hint: If using some form of technology, simply find all zeros as in Exercises 3.13 - 3.18. Otherwise, find the quadratic factor corresponding to the given complex zero, and long divide to find the other quadratic factor, which will then yield to the quadratic formula. (Complex arithmetic is treated at greater length in Chapter 8.)
3.19. with zero
3.20. with zero
In Exercises 3.21 - 3.24, find the real monic polynomial of least degree having the given numbers as its zeros.
3.21.
3.22.
3.23.
3.24.
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