5.2 Power functions and polynomial functions  (Page 3/19)

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Describe in words and symbols the end behavior of $\text{\hspace{0.17em}}f\left(x\right)=-5{x}^{4}.$

As $\text{\hspace{0.17em}}x\text{\hspace{0.17em}}$ approaches positive or negative infinity, $\text{\hspace{0.17em}}f\left(x\right)\text{\hspace{0.17em}}$ decreases without bound: as because of the negative coefficient.

Identifying polynomial functions

An oil pipeline bursts in the Gulf of Mexico, causing an oil slick in a roughly circular shape. The slick is currently 24 miles in radius, but that radius is increasing by 8 miles each week. We want to write a formula for the area covered by the oil slick by combining two functions. The radius $\text{\hspace{0.17em}}r\text{\hspace{0.17em}}$ of the spill depends on the number of weeks $\text{\hspace{0.17em}}w\text{\hspace{0.17em}}$ that have passed. This relationship is linear.

$r\left(w\right)=24+8w$

We can combine this with the formula for the area $\text{\hspace{0.17em}}A\text{\hspace{0.17em}}$ of a circle.

$A\left(r\right)=\pi {r}^{2}$

Composing these functions gives a formula for the area in terms of weeks.

$\begin{array}{ccc}\hfill A\left(w\right)& =& A\left(r\left(w\right)\right)\hfill \\ & =& A\left(24+8w\right)\hfill \\ & =& \pi {\left(24+8w\right)}^{2}\hfill \end{array}$

Multiplying gives the formula.

$A\left(w\right)=576\pi +384\pi w+64\pi {w}^{2}$

This formula is an example of a polynomial function . A polynomial function consists of either zero or the sum of a finite number of non-zero terms, each of which is a product of a number, called the coefficient of the term, and a variable raised to a non-negative integer power.

Polynomial functions

Let $\text{\hspace{0.17em}}n\text{\hspace{0.17em}}$ be a non-negative integer. A polynomial function    is a function that can be written in the form

$f\left(x\right)={a}_{n}{x}^{n}+...{a}_{1}x+{a}_{2}{x}^{2}+{a}_{1}x+{a}_{0}$

This is called the general form of a polynomial function. Each $\text{\hspace{0.17em}}{a}_{i}\text{\hspace{0.17em}}$ is a coefficient and can be any real number other than zero. Each expression $\text{\hspace{0.17em}}{a}_{i}{x}^{i}\text{\hspace{0.17em}}$ is a term of a polynomial function    .

Identifying polynomial functions

Which of the following are polynomial functions?

$\begin{array}{ccc}\hfill f\left(x\right)& =& 2{x}^{3}\cdot 3x+4\hfill \\ \hfill g\left(x\right)& =& -x\left({x}^{2}-4\right)\hfill \\ \hfill h\left(x\right)& =& 5\sqrt{x+2}\hfill \end{array}$

The first two functions are examples of polynomial functions because they can be written in the form $\text{\hspace{0.17em}}f\left(x\right)={a}_{n}{x}^{n}+...+{a}_{2}{x}^{2}+{a}_{1}x+{a}_{0},\text{\hspace{0.17em}}$ where the powers are non-negative integers and the coefficients are real numbers.

• $f\left(x\right)\text{\hspace{0.17em}}$ can be written as $\text{\hspace{0.17em}}f\left(x\right)=6{x}^{4}+4.$
• $g\left(x\right)\text{\hspace{0.17em}}$ can be written as $\text{\hspace{0.17em}}g\left(x\right)=-{x}^{3}+4x.$
• $h\left(x\right)\text{\hspace{0.17em}}$ cannot be written in this form and is therefore not a polynomial function.

Identifying the degree and leading coefficient of a polynomial function

Because of the form of a polynomial function, we can see an infinite variety in the number of terms and the power of the variable. Although the order of the terms in the polynomial function is not important for performing operations, we typically arrange the terms in descending order of power, or in general form. The degree    of the polynomial is the highest power of the variable that occurs in the polynomial; it is the power of the first variable if the function is in general form. The leading term    is the term containing the highest power of the variable, or the term with the highest degree. The leading coefficient    is the coefficient of the leading term.

Terminology of polynomial functions

We often rearrange polynomials so that the powers are descending.

When a polynomial is written in this way, we say that it is in general form.

Given a polynomial function, identify the degree and leading coefficient.

1. Find the highest power of $\text{\hspace{0.17em}}x\text{\hspace{0.17em}}$ to determine the degree function.
2. Identify the term containing the highest power of $\text{\hspace{0.17em}}x\text{\hspace{0.17em}}$ to find the leading term.
3. Identify the coefficient of the leading term.

what are you up to?
nothing up todat yet
Miranda
hi
jai
hello
jai
Miranda Drice
jai
aap konsi country se ho
jai
which language is that
Miranda
I am living in india
jai
good
Miranda
what is the formula for calculating algebraic
I think the formula for calculating algebraic is the statement of the equality of two expression stimulate by a set of addition, multiplication, soustraction, division, raising to a power and extraction of Root. U believe by having those in the equation you will be in measure to calculate it
Miranda
state and prove Cayley hamilton therom
hello
Propessor
hi
Miranda
the Cayley hamilton Theorem state if A is a square matrix and if f(x) is its characterics polynomial then f(x)=0 in another ways evey square matrix is a root of its chatacteristics polynomial.
Miranda
hi
jai
hi Miranda
jai
thanks
Propessor
welcome
jai
What is algebra
algebra is a branch of the mathematics to calculate expressions follow.
Miranda
Miranda Drice would you mind teaching me mathematics? I think you are really good at math. I'm not good at it. In fact I hate it. 😅😅😅
Jeffrey
lolll who told you I'm good at it
Miranda
something seems to wispher me to my ear that u are good at it. lol
Jeffrey
lolllll if you say so
Miranda
but seriously, Im really bad at math. And I hate it. But you see, I downloaded this app two months ago hoping to master it.
Jeffrey
which grade are you in though
Miranda
oh woww I understand
Miranda
Jeffrey
Jeffrey
Miranda
how come you finished in college and you don't like math though
Miranda
gotta practice, holmie
Steve
if you never use it you won't be able to appreciate it
Steve
I don't know why. But Im trying to like it.
Jeffrey
yes steve. you're right
Jeffrey
so you better
Miranda
what is the solution of the given equation?
which equation
Miranda
I dont know. lol
Jeffrey
Miranda
Jeffrey
answer and questions in exercise 11.2 sums
how do u calculate inequality of irrational number?
Alaba
give me an example
Chris
and I will walk you through it
Chris
cos (-z)= cos z .
cos(- z)=cos z
Mustafa
what is a algebra
(x+x)3=?
6x
Obed
what is the identity of 1-cos²5x equal to?
__john __05
Kishu
Hi
Abdel
hi
Ye
hi
Nokwanda
C'est comment
Abdel
Hi
Amanda
hello
SORIE
Hiiii
Chinni
hello
Ranjay
hi
ANSHU
hiiii
Chinni
h r u friends
Chinni
yes
Hassan
so is their any Genius in mathematics here let chat guys and get to know each other's
SORIE
I speak French
Abdel
okay no problem since we gather here and get to know each other
SORIE
hi im stupid at math and just wanna join here
Yaona
lol nahhh none of us here are stupid it's just that we have Fast, Medium, and slow learner bro but we all going to work things out together
SORIE
it's 12
what is the function of sine with respect of cosine , graphically
tangent bruh
Steve
cosx.cos2x.cos4x.cos8x
sinx sin2x is linearly dependent
what is a reciprocal
The reciprocal of a number is 1 divided by a number. eg the reciprocal of 10 is 1/10 which is 0.1
Shemmy
Reciprocal is a pair of numbers that, when multiplied together, equal to 1. Example; the reciprocal of 3 is ⅓, because 3 multiplied by ⅓ is equal to 1
Jeza
each term in a sequence below is five times the previous term what is the eighth term in the sequence
I don't understand how radicals works pls
How look for the general solution of a trig function