H. Algebra Polynomial Functions

Transcription

1 H. Algebra 6.1 Polynomial Functions A monomial is an epression that is either a real number, a variable or a product of real numbers and variables with whole number eponents. A polynomial is a monomial or the sum or difference of monomials. Any polynomial is made up of monomial pieces. Standard Form of a Polynomial Descending order that lists monomial terms by decreasing powers Degree of a Polynomial largest degree of any term of the polynomial Write each polynomial in standard form. Then classify it by degree and number of terms ( ) (3 5 8) 5. 3 ( ) ( 5 8) LINEAR QUADRATIC CUBIC QUARTIC

2 End Behavior: (pg. 306) Degree is EVEN Degree is ODD Leading Coefficient: POSITIVE Leading Coefficient: NEGATIVE Practice: Describe the end behavior of each polynomial function. 1. f ( ) 3. f ( ) f ( ) f ( ) f ( ) 5 6. f ( ) 5

3 Modeling Data with a Polynomial Function We have already used a linear and quadratic function to model data. Sometimes you can fit data more closely by using a polynomial model degree of three or greater. 1. Use your calculator to determine whether a linear model, quadratic model, or cubic model best fits the values in the table. Use the model to predict the value for y when = 5. X Y The table below shows world gold production for several years. Find a quartic function to model the data. Use it to estimate production in Year Production (millions of troy ounces)

4 H. Algebra 6. Polynomial and Linear Factors Writing a Polynomial in Standard Form 1. Write the epression ( + 1)( + )( + 3) as a polynomial in standard form.. Write the epression ( + 1)( + 1)( + ) as a polynomial in standard form. 3. Write the epression ( 1)( + 3)( + 4) as a polynomial in standard form. Writing a Polynomial in Factored Form 4. Write in factored form. 5. Write in factored form. 6. Write in factored form.

5 Applications: Polynomial Functions Volume of a Bo (V = L * W * H) 7. Panda Incorporated has asked its employees to design an open-top bo made from a piece of cardboard that is 36 inches on each side. It is to be made by cutting equal squares in the corners and turning up the sides. a. Label the sides using as the bo height when the corners are turned up. b. Write the equation in terms of that represents the volume of the bo. c. Describe a realistic domain. d. What dimensions of the bo will produce a maimum volume? e. What is the maimum volume? Relative Maimum: the greatest y-value of the points in a particular region of a graph. Relative Minimum: the least y-value of the points in a particular region of a graph.

6 8. Several popular models of carry-on luggage have a length of 10 inches greater than their depth. To comply with airline regulations, the sum of the length, width and height must not eceed 40 inches. a. Write a function V for the volume in terms of the depth. b. Describe a realistic domain. c. What is the maimum possible volume of a piece of luggage? What are the corresponding dimensions? Factors and Zeros (Roots) of a Polynomial Function If a polynomial is in factored form, you can use the Zero Product Property to find the values that will make the equation equal to zero. 9. Find the zeros of f() = ( - )( + 1) ( 3) and graph 10. Find the zeros of f() = ( + 3)( 4) ( 5) and graph

7 You can reverse the process and write linear factors when you are given the zeros. This relationship is described by the factor theorem. Factor Theorem: The epression a is a linear factor of a polynomial if and only if the value a is a zero (root) of the related polynomial function. Writing a Polynomial Function from its Zeros 11. Write a polynomial function in standard form with zeros at, 3, and Write a polynomial function in standard form with zeros 4, - and Write a polynomial function in standard form with zeros 4, - and 0. Multiplicity: equal to the number of times the zero occurs Repeated zeros (a.k.a repeated root) Finding the Multiplicity of a Zero 14. Find any multiple zeros of y = and state the multiplicity 15. For each function, find any multiple zeros and state the multiplicity a. y = ( ) ( + 1)( 3) b. y =

8 H. Algebra 6.3 Dividing Polynomials You can use long division to help find all zeros of a polynomial function. Reminder: divisor dividend Find the following quotients BY HAND. Do not use decimals; write remainders Divide: ( 3 4 1) ( 4) Practice: Find each quotient using long division. 1. ( ) ( 3 1). ( ) ( 3)

9 3. ( 3 4 4) ( ) 4. ( ) ( 6 9) If your divisor is a linear epression (degree of 1), you can use this method: 3 Synthetic Division is a method used to divide polynomials. ( 3 4 1) ( 3) Find the quotient: ( 3 9 9) ( 1) Practice: Find each quotient using Synthetic Division ( 3 4 1) ( 3). ( 3 ) ( 1) 3 3. ( 4) ( ) 4. ( ) ( 3)

10 When you divide by a linear factor ( r) and there is NO REMAINDER, that linear factor is a factor of the function; f(r) = 0 When you divide by a linear factor and there is A REMAINDER, then the function is not divisible by that factor; f(r) 0 First, determine whether or not the function is divisible by the given factor. If it is, factor the function completely ; 3 ) ( f. 4; 4 ) ( f ; 6 ) ( 3 f ; 6 3 ) ( 3 f ; 5 ) ( 3 f ; 4 5 ) ( 4 f

11 Find all zeros of each function. One of the zeros is given f ( ) ; 8. f ( ) ; f ( ) ; f ( ) ; 3

12 6.7 Permutations and Combinations Eample 1 With Replacement- Eight pieces of paper are numbered from 1 to 8 and placed in a bo. One paper is drawn from the bo and the number is written down. The piece of paper is replaced in the bo. Then a second piece of paper is drawn. That number is written down. Finally, the numbers are added together. How many different ways can a total of 1 be obtained? Eample Without Replacement- Eight pieces of paper are numbered from 1 to 8 and placed in a bo. Two pieces of paper are drawn at the same time and the numbers are added together. How many different ways can a total of 1 be obtained? The Fundamental Counting Principle Le E 1 and E be two events. The first even E 1 can occur in m 1 different ways. After E 1 has occurred, E can occur in m different ways. The number of ways that the two events can occur is m 1 X m Eample- How many different pairs of letters from the English alphabet are possible? Eample- How many different telephone numbers are possible within each area code. (Cannot begin with 0 or 1) Permutation of n different elements is an ordering of the elements such that one element is first, one is second, one is third and so on. Eample- How many different permutations are possible for the letters A B C D E F

13 Number of Permutations of n Elements: The number of permutations of n elements is Sometimes you may be interested in ordering a subset of a collection of elements rather than an entire collection. You may want to choose (and order) r elements out of a collection of n elements. Such an ordering is called a permutation of n elements taken r at a time. Eample- 8 horses are running in a race. In how many different ways can these horses come in first, second and third? (assume no ties) Permutations of n Elements Taken r at a Time The number of permutations of n elements taken r at a time is ** Eample- In how many distinguishable ways can the letters in BANANA be written? Combinations When you count the number of possible permutations of a set of elements, order is important. As a final topic in this section, you will look at a method of selecting subsets of a larger set in which order is not important. Such subsets are called combinations of n elements taken r at a time. Eample- {A, B, C} and {B, A, C} are the same because they contain the same three elements. You would count only one of the two sets. Eample- In how many different ways can three letters be chosen from the letters A B C D and E? (order does not matter)

14 Combinations of n Elements Taken r at a Time The number of combinations of n elements taken r at time is Eample- The standard poker hand consists of five cards dealt from 5 cards. How many different poker hands are possible? Eample- Find the total number of subsets of a set that has 10 elements Eercises: 1.Evaluate 6 P and 6 C. A local building company is hiring etra summer help. They need four additional employees to work outside in the lumber yard and three more to work in the store. In how many ways can these positions be filled if there are 10 applicants for the outside work and five for the inside work? 3. In how many distinguishable ways can the letters CALCULUS be written? 6.5 The Rational Root Theorem If q p is in simplest form and is a rational root of the polynomial equation n n1 an an 1... a1 a0 factor of a n. 0 with integer coefficients, then p must be a factor of a 0 and q must be a You can use the rational root theorem to find any rational roots of a polynomial equation with integer coefficients. Eample- Find the rational roots of = 0

15 Eample- Find the rational roots of = 0 Eample- Using the Rational Root Theorem Find all roots of = 0

16 Eample- Using the Rational Root Theorem Find all roots of = 0 Eample- Using the Rational Root Theorem Find all roots of = The Binomial Theorem To epand a binomial being raised to a power, first multiply, then write in standard form: (a + b) = (a + b) 3 = Pascal s Triangle: Triangular array of numbers formed by first lining the border with 1 s and then placing the sum of two adjacent numbers within a row between and underneath the original two numbers:

17 Using Pascal s Triangle: Epand (a + b) 6 Eample- Epand ( ) 4 Binomial Theorem- For every integer n, (a + b) n = Eample- Using Binomial Theorem- epand (g + h) 4 Eample- Using Binomial Theorem-epand (v + w) 9 Eample- Using Binomial Theorem- epand (c ) 5

18 Eample- Use Binomial Theorem- epand ( y) 8 Eample- Use Binomial Theorem- epand (3 y) 4

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