# 3.2 Polynomial function  (Page 3/3)

 Page 3 / 3

## Identity function

The dependent (y) and independent (x) variables have same value. Identity function is similar in concept to that of identity relation which consists of relation of an element of a set with itself. It is a linear function in which m=1 and c=0. Identity function form is represented as :

$y=\mathrm{f\left(x\right)}=x$

The graph of identity function is a straight line bisecting first and third quadrants of coordinate system. Note that slope of straight line is 45°. It is clear from the graph that its domain and range both are real number set R.

The general form of quadratic function is :

$\mathrm{f\left(x\right)}=a{x}^{2}+bx+c;\phantom{\rule{1em}{0ex}}a,b,c\in R;\phantom{\rule{1em}{0ex}}a\ne 0$

We shall discuss quadratic function in detail in a separate module and hence discussion of this function is not taken up here.

## Graph of polynomial function

Graph of polynomial is continuous and non-periodic. If degree is greater than 1, then it is a non-linear graph. Polynomial graphs are analyzed with the help of function properties like intercepts, slopes, concavity, and end behaviors. The may or may not intersect x-axis. This means that it may or may not have real roots. As maximum number of roots of a polynomial is at the most equal to the order of polynomial, we can deduce that graph can at the most intersect x-axis “n” times as maximum numbers of real roots are “n”.

The fact that graph of polynomial is continuous suggests two interesting inferences :

1: If there are two values of polynomial f(a) and f(b) such that f(a)f(b)<0, then there are at least 1 or an odd numbers of real roots between a and b. The condition f(a)f(b)<0 means that function values f(a) and f(b) lie on the opposite sides of x-axis. Since graph is continuous, it is bound to cross x-axis at least once or odd times. As such, there are at least 1 or odd numbers of real roots (as shown in the left figure down).

2 : If there are two values of polynomial f(a) and f(b) such that f(a)f(b)>0, then there are either no real roots or there are even numbers of real roots between a and b. The condition f(a)f(b)>0 means that function values f(a) and f(b) are either both negative or both positive i.e. they lie on the same side of x - axis. Since graph is continuous, it may not cross at all or may cross x-axis even times (as shown in the right figure above). Clearly, there is either no real root or there are even numbers of real roots.

We shall study graphs of quadratic polynomials in a separate module. Further, other graphs will be discussed in appropriate context, while discussing a particular function. Here, we present two monomial quadratic graphs $y={x}^{2}$ and $y={x}^{3}$ . These graphs are important from the point of view of generalizing graphs of these particular polynomial structure. The nature of graphs $y={x}^{n}$ , where “n” is even integer greater than equal to 2, is similar to the graph of $y={x}^{2}$ . We should emphasize that the shape of curve simply generalizes the nature of graph – we need to draw them actually, if we want to draw graph of a particular monomial function. However, we shall find that these generalizations about nature of curve lets us know a great deal about the monomial polynomial. In particular, we can conclude that their domain and range are real number set R.

Similarly, the nature of graphs $y={x}^{n}$ , where “n” is odd number integer greater than 2, is similar to the graph of $y={x}^{3}$ .

how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Do somebody tell me a best nano engineering book for beginners?
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
what is nano technology
what is system testing?
preparation of nanomaterial
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
what is system testing
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
how did you get the value of 2000N.What calculations are needed to arrive at it
Privacy Information Security Software Version 1.1a
Good
Berger describes sociologists as concerned with
What is power set
Period of sin^6 3x+ cos^6 3x
Period of sin^6 3x+ cos^6 3x