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Unit-2:Polymonials (Core) - New Indian Model School, Dubai

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CLASS<br />

X<br />

CBSE-i<br />

A L G E B R A ( C O R E )<br />

POLYNOMIALS<br />

UNIT - 2<br />

Shiksha Kendra, 2, Community Centre, Preet Vihar, Delhi-110 092 India


CBSE-i<br />

A L G E B R A ( C O R E )<br />

POLYNOMIALS<br />

UNIT - 2<br />

CLASS-X<br />

Shiksha Kendra, 2, Community Centre, Preet Vihar, Delhi-110 092 India


The CBSE-International is grateful for permission to reproduce and/or<br />

translate copyright material used in this publication. The<br />

acknowledgements have been included wherever appropriate and<br />

sources from where the material has been taken duly mentioned. In<br />

case anything has been missed out, the Board will be pleased to rectify<br />

the error at the earliest possible opportunity.<br />

All Rights of these documents are reserved. No part of this publication<br />

may be reproduced, printed or transmitted in any form without the<br />

prior permission of the CBSE-i. This material is meant for the use of<br />

schools who are a part of the CBSE-International only.


Preface<br />

The Curriculum initiated by Central Board of Secondary Education -International (CBSE-i) is a progressive step in making<br />

the educational content and methodology more sensitive and responsive to the global needs. It signifies the emergence of a<br />

fresh thought process in imparting a curriculum which would restore the independence of the learner to pursue the<br />

learning process in harmony with the existing personal, social and cultural ethos.<br />

The Central Board of Secondary Education has been providing support to the academic needs of the learners worldwide. It<br />

has about 11500 schools affiliated to it and over 158 schools situated in more than 23 countries. The Board has always been<br />

conscious of the varying needs of the learners in countries abroad and has been working towards contextualizing certain<br />

elements of the learning process to the physical, geographical, social and cultural environment in which they are engaged.<br />

The International Curriculum being designed by CBSE-i, has been visualized and developed with these requirements in<br />

view.<br />

The nucleus of the entire process of constructing the curricular structure is the learner. The objective of the curriculum is to<br />

nurture the independence of the learner, given the fact that every learner is unique. The learner has to understand,<br />

appreciate, protect and build on values, beliefs and traditional wisdom, make the necessary modifications, improvisations<br />

and additions wherever and whenever necessary.<br />

The recent scientific and technological advances have thrown open the gateways of knowledge at an astonishing pace. The<br />

speed and methods of assimilating knowledge have put forth many challenges to the educators, forcing them to rethink<br />

their approaches for knowledge processing by their learners. In this context, it has become imperative for them to<br />

incorporate those skills which will enable the young learners to become 'life long learners'. The ability to stay current, to<br />

upgrade skills with emerging technologies, to understand the nuances involved in change management and the relevant<br />

life skills have to be a part of the learning domains of the global learners. The CBSE-i curriculum has taken cognizance of<br />

these requirements.<br />

The CBSE-i aims to carry forward the basic strength of the <strong>Indian</strong> system of education while promoting critical and<br />

creative thinking skills, effective communication skills, interpersonal and collaborative skills along with information and<br />

media skills. There is an inbuilt flexibility in the curriculum, as it provides a foundation and an extension curriculum, in all<br />

subject areas to cater to the different pace of learners.<br />

The CBSE has introduced the CBSE-i curriculum in schools affiliated to CBSE at the international level in 2010 and is now<br />

introducing it to other affiliated schools who meet the requirements for introducing this curriculum. The focus of CBSE-i is<br />

to ensure that the learner is stress-free and committed to active learning. The learner would be evaluated on a continuous<br />

and comprehensive basis consequent to the mutual interactions between the teacher and the learner. There are some nonevaluative<br />

components in the curriculum which would be commented upon by the teachers and the school. The objective<br />

of this part or the core of the curriculum is to scaffold the learning experiences and to relate tacit knowledge with formal<br />

knowledge. This would involve trans-disciplinary linkages that would form the core of the learning process. Perspectives,<br />

SEWA (Social Empowerment through Work and Action), Life Skills and Research would be the constituents of this '<strong>Core</strong>'.<br />

The <strong>Core</strong> skills are the most significant aspects of a learner's holistic growth and learning curve.<br />

The International Curriculum has been designed keeping in view the foundations of the National Curricular Framework<br />

(NCF 2005) NCERT and the experience gathered by the Board over the last seven decades in imparting effective learning to<br />

millions of learners, many of whom are now global citizens.<br />

The Board does not interpret this development as an alternative to other curricula existing at the international level, but as<br />

an exercise in providing the much needed <strong>Indian</strong> leadership for global education at the school level. The International<br />

Curriculum would evolve on its own, building on learning experiences inside the classroom over a period of time. The<br />

Board while addressing the issues of empowerment with the help of the schools' administering this system strongly<br />

recommends that practicing teachers become skillful learners on their own and also transfer their learning experiences to<br />

their peers through the interactive platforms provided by the Board.<br />

I profusely thank Shri G. Balasubramanian, former Director (Academics), CBSE, Ms. Abha Adams and her team and Dr.<br />

Sadhana Parashar, Head (Innovations and Research) CBSE along with other Education Officers involved in the<br />

development and implementation of this material.<br />

The CBSE-i website has already started enabling all stakeholders to participate in this initiative through the discussion<br />

forums provided on the portal. Any further suggestions are welcome.<br />

Vineet Joshi<br />

Chairman


Advisory<br />

Shri Vineet Joshi, Chairman, CBSE<br />

Shri Shashi Bhushan, Director(Academic), CBSE<br />

Ideators<br />

English :<br />

Ms. Sarita Manuja<br />

Ms. Renu Anand<br />

Ms. Gayatri Khanna<br />

Ms. P. Rajeshwary<br />

Ms. Neha Sharma<br />

Ms. Sarabjit Kaur<br />

Ms. Ruchika Sachdev<br />

Geography:<br />

Ms. Deepa Kapoor<br />

Ms. Bharti Dave<br />

Ms. Bhagirathi<br />

Ms. Archana Sagar<br />

Ms. Manjari Rattan<br />

Acknowledgements<br />

Mathematics :<br />

Dr. K.P. Chinda<br />

Mr. J.C. Nijhawan<br />

Ms. Rashmi Kathuria<br />

Ms. Reemu Verma<br />

Political Science:<br />

Ms. Sharmila Bakshi<br />

Ms. Srelekha Mukherjee<br />

Conceptual Framework<br />

Shri G. Balasubramanian, Former Director (Acad), CBSE<br />

Ms. Abha Adams, Consultant, Step-by-Step <strong>School</strong>, Noida<br />

Dr. Sadhana Parashar, Head (I & R),CBSE<br />

Ms. Aditi Misra Ms. Anuradha Sen Ms. Jaishree Srivastava Dr. Rajesh Hassija<br />

Ms. Amita Mishra Ms. Archana Sagar Dr. Kamla Menon Ms. Rupa Chakravarty<br />

Ms. Anita Sharma Ms. Geeta Varshney Dr. Meena Dhami Ms. Sarita Manuja<br />

Ms. Anita Makkar Ms. Guneet Ohri Ms. Neelima Sharma Ms. Seema Rawat<br />

Dr. Anju Srivastava Dr. Indu Khetrapal Dr. N. K. Sehgal Dr. Uma Chaudhry<br />

Material Production Groups: Classes IX-X<br />

Science :<br />

Ms. Charu Maini<br />

Ms. S. Anjum<br />

Ms. Meenambika Menon<br />

Ms. Novita Chopra<br />

Ms. Neeta Rastogi<br />

Ms. Pooja Sareen<br />

Economics:<br />

Ms. Mridula Pant<br />

Mr. Pankaj Bhanwani<br />

Ms. Ambica Gulati<br />

Material Production Groups: Classes VI-VIII<br />

History :<br />

Ms. Jayshree Srivastava<br />

Ms. M. Bose<br />

Ms. A. Venkatachalam<br />

Ms. Smita Bhattacharya<br />

English :<br />

Science :<br />

Mathematics :<br />

Geography:<br />

Ms. Rachna Pandit<br />

Dr. Meena Dhami<br />

Ms. Seema Rawat<br />

Ms. Suparna Sharma<br />

Ms. Neha Sharma<br />

Mr. Saroj Kumar<br />

Ms. N. Vidya<br />

Ms. Leela Grewal<br />

Ms. Sonia Jain<br />

Ms. Rashmi Ramsinghaney<br />

Ms. Mamta Goyal<br />

History :<br />

Ms. Dipinder Kaur<br />

Ms. Seema kapoor<br />

Ms. Chhavi Raheja<br />

Ms. Leeza Dutta<br />

Ms. Sarita Ahuja<br />

Ms. Priyanka Sen<br />

Political Science:<br />

Ms. Kalpana Pant<br />

Dr. Kavita Khanna<br />

Ms. Kanu Chopra<br />

Ms. Keya Gupta<br />

Ms. Shilpi Anand<br />

Coordinators:<br />

Dr. Sadhana Parashar, Ms. Sugandh Sharma, Dr. Srijata Das, Dr. Rashmi Sethi,<br />

Head (I and R) E O (Com) E O (Maths) E O (Science)<br />

Shri R. P. Sharma, Consultant Ms. Ritu Narang, RO (Innovation) Ms. Sindhu Saxena, R O (Tech) Shri Al Hilal Ahmed, AEO<br />

Ms. Seema Lakra, S O<br />

Material Production Group: Classes I-V<br />

Dr. Indu Khetarpal Ms. Rupa Chakravarty Ms. Anita Makkar Ms. Nandita Mathur<br />

Ms. Vandana Kumar Ms. Anuradha Mathur Ms. Kalpana Mattoo Ms. Seema Chowdhary<br />

Ms. Anju Chauhan Ms. Savinder Kaur Rooprai Ms. Monika Thakur Ms. Ruba Chakarvarty<br />

Ms. Deepti Verma Ms. Seema Choudhary Mr. Bijo Thomas Ms. Mahua Bhattacharya<br />

Ms. Ritu Batra<br />

Ms. Kalyani Voleti<br />

Ms. Preeti Hans, Proof Reader


Content<br />

1. Syllabus 1<br />

2. Scope Document 2<br />

3. Material Resource 5<br />

• 2.1 Introduction of <strong>Unit</strong> 5<br />

• 2.2 Value of a Polynomial at a point 7<br />

• 2.3 Zero of a Polynomial 7<br />

• 2.4 Relation between zeroes and coefficients 10<br />

• 2.5 Geometrical representation of zeroes of polynomial 12<br />

• 2.6 Reading zeroes of linear and quadratic polynomial from graph 16<br />

• 2.7 Division of Polynomials 18<br />

4. Teacher's Support Material 21<br />

• 2.8 Activity 1 - Warm up (W1) 22<br />

• 2.9 Activity 2 - Warm up (W2) 24<br />

• 2.10 Activity 3 - Pre Content (P1) 26<br />

• 2.11 Activity 4 - Content Worksheet (CW1) 26<br />

• 2.12 Activity 5 - Content Worksheet (CW2) 27<br />

• 2.13 Activity 6 - Content Worksheet (CW3) 27<br />

• 2.14 Activity 7 - Content Worksheet (CW4) 28<br />

• 2.15 Activity 8 - Content Worksheet (CW5) 28<br />

• 2.16 List of useful resources 29


Content<br />

5. Students' Support Material 31<br />

• Worksheet 1 - Warm up (W1 & W2) 32<br />

• Self assessment Rubric 1 34<br />

• Worksheet 2 - Pre Content (P1) 35<br />

• Worksheet 3 - Self assessment Rubric 2 36<br />

• Worksheet 4 - Content (CW1) 37<br />

• Worksheet 5 - Self assessment Rubric 3 39<br />

• Worksheet 6 - Content (CW2) 40<br />

• Worksheet 7 - Self assessment Rubric 4 41<br />

• Worksheet 8 - Content (CW3) 42<br />

• Worksheet 9 - Self assessment Rubric 5 44<br />

• Worksheet 10 - Content (CW4) 45<br />

• Worksheet 11 - Self assessment Rubric 6 47<br />

• Worksheet 12 - Content (CW5) 48<br />

• Worksheet 13 - Self assessment Rubric 7<br />

49<br />

• Worksheet 14 - Post Content (PCW1) 50<br />

• Worksheet 15 - Post Content (PCW2) 51<br />

6. Assessment Guidance Plan 53


SYLLABUS UNIT 2 :<br />

ALGEBRA (CORE)-POLYNOMIALS<br />

Polynomial<br />

Zeroes of polynomial<br />

Division algorithm<br />

Recapitulation of vocabulary of polynomials<br />

in one variable - coefficient, terms, degree,<br />

constant, linear, quadratic, cubic polynomial<br />

Zero of linear polynomial, zeroes of quadratic<br />

polynomial, finding zeroes of polynomial by<br />

splitting middle terms, relation between<br />

zeroes and coefficients. Geometrical<br />

representation of zeroes of polynomial,<br />

reading zeroes of linear and quadratic<br />

polynomial from graph.<br />

Dividend= divisor x quotient + remainder<br />

Division of quadratic polynomial by linear<br />

polynomial<br />

Division of cubic polynomial by linear<br />

polynomial<br />

Division of cubic polynomial by quadratic<br />

polynomial<br />

MATHEMATICS UNIT - 2<br />

1


SCOPE DOCUMENT<br />

Key terms<br />

1. Zeroes of a polynomial<br />

2. Cubic polynomial<br />

3. Division algorithm<br />

Learning Objectives<br />

1. To tell the possible number of zeroes for a given polynomial.<br />

2. To find zero of a linear polynomial algebraically.<br />

3. To find zeroes of a quadratic polynomial algebraically.<br />

4. To find zeroes of a cubic polynomial algebraically.<br />

5. To understand the geometrical meaning of zeroes.<br />

6. To read the zeroes of a polynomial from given graph.<br />

7. To find the polynomial when zeroes are known.<br />

8. To divide the linear polynomial by a linear polynomial.<br />

9. To divide the quadratic polynomial by a linear polynomial.<br />

10. To divide the cubic polynomial by a linear polynomial.<br />

11. To divide the cubic polynomial by a quadratic polynomial.<br />

12. To express the division of two polynomials using division algorithm<br />

2<br />

MATHEMATICS UNIT - 2


Extension Activities:<br />

Finance<br />

1. Find the zeroes of a cubic polynomial by the method of grouping.<br />

2. Find the zeroes of a bi-quadratic polynomial using division.<br />

Cross Curricular Links : Polynomials define simple curves in the language of mathematics so<br />

that they may be easily analyzed and modified. Simple curves can be combined to closely<br />

approximate more complicated curves. Planets, weather etc. move in curves. Mechanical<br />

forces, chemical and biological processes, etc. are not constant but change over space and time.<br />

These changes and other changes like fluctuations in the economy can be approximated by<br />

curves. Also, televisions, computers, phones, music players, etc. all receive signals that are<br />

sine waves (curves). Polynomials are the building blocks of all these sciences.<br />

Assessment of present value is used in loan calculations and company valuation. It involves<br />

polynomials that back interest accumulation out of future liquid transactions, with the aim of<br />

finding an equivalent liquid (present, cash, or in-hand) value. Tax and economic calculations<br />

can usually be written as polynomials as well.<br />

Electronics<br />

Electronics use many polynomials. The definition of resistance, V=IR, is a polynomial relating<br />

the resistance from a resistor to the current through it and the potential drop across it.<br />

Curve Fitting<br />

Polynomials are fit to data points in both regression and interpolation. In regression, a large<br />

number of data points is fit with a function, usually a line: y=mx+b. The equation may have<br />

more than one "x" (more than one dependent variable), which is called multiple linear.<br />

In interpolation, short polynomials are joined tegether so they pass through all the data points.<br />

For those who are curious to research this more, the name of some of the polynomials used for<br />

interpolation are called "Lagrange polynomials", "cubic splines" and "Bezier splines".<br />

Chemistry<br />

Polynomials come up often in chemistry. Gas equations relating diagnostic parameters can<br />

usually be written as polynomials, such as the ideal gas law: PV=nRT (where 'n' is mole count<br />

and 'R' is a proportionality constant).<br />

MATHEMATICS UNIT - 2<br />

3


Formulas of molecules in concentration at equilibrium also can be written as polynomials. For<br />

example, if A, B and C are the concentrations in solution of OH-, H2O+, and H2O respectively,<br />

then the equilibrium concentration equation can be written in terms of the corresponding<br />

equilibrium constant K: KC=AB.<br />

Physics and Engineering<br />

Physics and engineering are fundamentally studies in proportionality. If a stress is increased,<br />

how much does the beam deflect? If a trajectory is fired at a certain angle, how far away will it<br />

land?<br />

Polynomials are really useful in calculating projectile paths as the physics equation for<br />

projectile motion is:<br />

s=ut + 0.5 at ²<br />

this is a quadratic<br />

Other polynomials can be derived (calculus) to find the rate of change.<br />

Such as if you have a distance time graph, d (t) = t² + 5 for example, you can find the velocity of<br />

that graph at any point in time.<br />

Read more :<br />

How are Polynomials used in Life? |eHow.com<br />

http://www.ehow.com/about_5479798_polynomials-used-life.html#ixzz1Inv2GL6n<br />

4<br />

MATHEMATICS UNIT - 2


2.1 Introduction of the unit:<br />

In previous Classes you have studied about the polynomials. Let us recall all<br />

concepts learnt.<br />

Polynomial is an algebraic expression in one variable, say x .It is the sum of two or<br />

n<br />

more terms of the form ax , where a is real number and x is a non negative integer.<br />

Polynomial can be written in the form<br />

2 n-2 n-1 n<br />

a<br />

0<br />

+ a1x + a2x + .....................+ an-2x + an-1x + a<br />

n<br />

x<br />

where a , a , a ,.......a , a , a are real number and are known as coefficients and are<br />

0 1 2 n-2 n-1 n<br />

known as non-negative integers.<br />

Some examples of polynomial are<br />

2 8 2 3 2<br />

x +5x+6, x +8x +15x+9, x +2x +x+4<br />

7 The coefficient of highest power term is known as leading coefficient.<br />

8 The coefficient of a term with power 0 is called a constant,<br />

3<br />

In 3x +5x+7. 7 is a constant and 3 is the leading coefficient.<br />

Let us revise these terms.<br />

What is a monomial? Polynomial with one term is known as monomial<br />

Examples of monomials are<br />

5 3<br />

15, 24x, 12y , -100m<br />

MATERIAL RESOURCES<br />

What is a binomial? Polynomial with two terms is known as binomial<br />

Examples of binomials are<br />

• 16y² + 25y<br />

• -112x³ - 23x<br />

• 31x + 5x²<br />

MATHEMATICS UNIT - 2<br />

5


What is a trinomial? A trinomial is a polynomial with three terms<br />

Examples of trinomials are:<br />

2<br />

• 5x + 6x + 7<br />

3 2<br />

• -12x + 63x - 25x<br />

Degree of a Polynomial<br />

Power of variable in each term is known as degree of that term. For example for a<br />

3 2<br />

polynomial p(x) = 2x + 5x +7 x+ 6<br />

Term<br />

Degree of corresponding term<br />

3<br />

2x 3<br />

2<br />

5x 2<br />

7 x 1<br />

6 0<br />

The term with highest power determines the degree of a polynomial .In the above<br />

case the highest power is 3. So the degree of the polynomial is 3.<br />

If p(x) is a polynomial in x, the highest power of x in p(x) is called the degree of the<br />

polynomial p(x).Depending on the degree, a polynomials can be named as:<br />

Linear Polynomial: A polynomial whose degree is 1.<br />

Quadratic Polynomial: A polynomial whose degree is 2.<br />

Cubic Polynomial: A polynomial whose degree is 3.<br />

Degree Name Example<br />

0 constant 10<br />

1 linear 5x+2<br />

2 quadratic 5x² + 14x + 6<br />

3 cubic 12x³ + 3x + 7<br />

4 2<br />

4 quartic 30x + 2x + 24<br />

5<br />

5 quintic 2x + 3x + 1<br />

6<br />

MATHEMATICS UNIT - 2


2.2 Value of a polynomial at a point<br />

2<br />

Consider the polynomial p(x) = x + 5x - 3. When we put x = 1 in p(x), then we get<br />

2<br />

p(1) = 1 +5 × 1 - 3 = 3. The value '3', obtained by replacing x by 1 in p(x), is the value of<br />

given polynomial at x = 1.<br />

Now, consider p(x) = 5x+3<br />

p(0) = 5(0) +3 = 3<br />

p(1) = 5(1) +3 = 8<br />

p(2) = 5(2) +3 = 13<br />

In general, If p(x) is a polynomial in x, and if k is any real number, then the value<br />

obtained by replacing x by k in p(x), is called the value of p(x) at x = k, and is denoted by<br />

p(k).<br />

3 2<br />

What is the value of p(x) = 5x -3x -4x+1 at x= -3?<br />

3 2<br />

p(x) = 5x -3x -4x+1<br />

3 2<br />

p(-3)= 5(-3) -3(-3) -4(-3)+1<br />

Simplify and get the answer.<br />

2.3 Zero of a Polynomial<br />

In class 9 students have learnt the concept of finding zero of a linear polynomial.<br />

Definition:<br />

Zero of a polynomial is that value of x that makes the polynomial equal to 0. In other<br />

words, the number r is a zero of a polynomial P(x) if and only if P(r) = 0.<br />

Example 1: Consider a linear polynomial 5x + 7,<br />

To get its zero, we have to find the value of x, so that it becomes zero.<br />

Therefore 5x + 7 = 0<br />

⇒x = - 7/5<br />

Exercise: Find the zero of following linear polynomials:<br />

1. P(x) = 4x -3<br />

MATHEMATICS UNIT - 2<br />

7


2. Q(x) = 7x + 5/3<br />

3. R(t) = 9t- 4<br />

4. P(x) = 14x + 5<br />

2<br />

Example 2: Consider a quadratic polynomial x -5x+6,<br />

To get its zero, we have to find the value of x, so that it becomes zero.<br />

2<br />

⇒x -5x+6 = 0<br />

2<br />

⇒x -3x-2x+6 = 0<br />

⇒x(x-3) -2 (x-3) = 0<br />

⇒(x-3)(x-2) = 0<br />

⇒x = 3 or x= 2<br />

2.3.1 How many zeroes can a polynomial have?<br />

Number of zeroes of a polynomial depends on its degree. A polynomial of degree n can<br />

have at the most n number of zeroes.<br />

A polynomial of degree two can have at the most two zeroes.<br />

2<br />

Polynomial x + 2x +1 has only one zero i.e. -1.<br />

2<br />

Polynomial x + 3x+2 has two zeroes -1 and -2.<br />

A polynomial of degree 3 can have at the most three zeroes.<br />

Can you write a polynomial of degree three with one zero?<br />

Can you write a polynomial of degree three with two zeroes?<br />

Can you write a polynomial of degree three with three zeroes?<br />

It is possible to write a polynomial when the zeroes are known.<br />

To write a polynomial when its zeroes are known<br />

In the example 2 given above you may observe that 2 and 3 are zeroes of polynomial and<br />

x-2 and x-3 are factors of a given polynomial.<br />

8<br />

MATHEMATICS UNIT - 2


If a given polynomial p(x) can be factorised and can be written as (x-a) (x-b) (x-c)…..<br />

then the polynomial will become zero if any one of its factor is zero.<br />

Thus we can say that if a polynomial has zeroes as a and b , it will have factors as x-a and<br />

2<br />

x-b, then the polynomial will be (x-a)(x-b)=x -(a+b)x +ab.<br />

Example 3: Find a polynomial of degree 3 with zeroes as -2,1,3.<br />

Solution: If -2 is a zero of a polynomial then x+2 is a factor of polynomial. Similarly<br />

other factors are x-1 and x-3.Therefore polynomial is (x+2) (x-1) (x-3).<br />

3 2<br />

Simplify to get the required polynomial p(x)= x -2x -5x +6<br />

2.3.2 Finding zeroes of a polynomial using constant term and leading<br />

coefficient<br />

2<br />

Consider the polynomial q(x)=x - 6x +5.<br />

Here the constant term is 5.Its factor are say p=1 and 5.<br />

Here the leading coefficient is 1.its only factor is say q= 1.<br />

Divide the factors of the constant by the factors of leading coefficient i.e. find p/q. Take<br />

positive and negative values of p/q. Here 1,-1 and 5,-5 are obtained.<br />

Insert the numbers obtained in the polynomial,<br />

2<br />

Q (1) = (1) -6(1) +5=0<br />

2<br />

Q (5) = (5) - 6(5) +5 =0<br />

2<br />

Q (-1) = (-1) -6(-1) +5≠0<br />

2<br />

Q (-5) = (-5) -6(-5) +5≠0<br />

You may observe that 1 and 5 are zeroes of given polynomial.<br />

Note : Zeroes obtained in this manner are known as Rational Zeroes.<br />

3<br />

Examples 4: Find the roots of x -3x +2=0<br />

Solution: Here leading coefficient= 1.Its factors are q=1<br />

Constant term= 2. Its factors are p = 1 and 2<br />

So, p/q= 1 and 2<br />

MATHEMATICS UNIT - 2<br />

9


Take both positive and negative values of p/q=1,-1,2,-2<br />

3<br />

P(1)= (1) - 3(1)2 +2=0<br />

3<br />

P(-1)= (-1) - 3(-1)2 +2≠0<br />

3<br />

P(2)= (2) - 3(2)2 +2≠0<br />

3 2<br />

P(-2)= (-2) - 3(-2) +2≠0<br />

Therefore x=1 is a zero of the given polynomial. But the given polynomial is of degree 3,<br />

so it can have at the most three zeroes. From above method we are able to find only one<br />

zero. Other two zeroes in this case can be determined by dividing the given polynomial<br />

by x-1 as x-1 is one of the factors of given polynomial.<br />

We will first learn the division algorithm and then will learn further to find all zeroes of<br />

cubic polynomial.<br />

Example 5. Let P(x) = 5x³ - 4x² + 7x - 8. Find P (1).What do you conclude about the<br />

factors of P(x)?<br />

2.4 Relationship between zeroes and coefficients of a quadratic polynomial<br />

What is a quadratic polynomial?<br />

2<br />

A polynomial ax +bx+c, a ≠0, a, b, c, are real numbers is called a quadratic polynomial.<br />

Consider a quadratic polynomial 5x²+ 6x +1. To get its zero, we write 5x²+ 6x +1 = 0. This<br />

means we have to find the value (s) of the variable x which makes the given expression<br />

0.<br />

By splitting the middle term, we get 5x²+ 5 x +x +1 = 0.<br />

This means, 5x(x+1) + 1(x+1) = 0<br />

⇒(5x+1)(x+1) = 0<br />

⇒x = -1/5 or x = -1<br />

Therefore, the two zeroes are -1/5 and -1<br />

Now, find the sum of zeroes and product of zeroes<br />

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MATHEMATICS UNIT - 2


Sum of zeroes =<br />

- 1 5 -1= - 6 5<br />

Observe the coefficient of x and the coefficient of x² terms.<br />

We find that Sum of zeroes = -<br />

Coefficient of x<br />

coefficient of x²<br />

Now, find the product of zeroes<br />

Product of zeroes =<br />

- 1 5 x -1= 1 5<br />

2<br />

Observe the constant term and the coefficient of x terms.<br />

We find that Product of zeroes =<br />

Coefficient term<br />

coefficient of x²<br />

In a quadratic polynomial ax²+bx+c, a 0, a, b, c, are real numbers<br />

Sum of zeroes = -<br />

Product of zeroes =<br />

Coefficient of x<br />

coefficient of x²<br />

Coefficient term<br />

coefficient of x²<br />

Example: Consider a quadratic polynomial 2x²-8x + 6<br />

By splitting the middle term we get,<br />

2x²-8x+6 = (2x-2)(x-3)<br />

= 2(x-1)(x-3)<br />

Zeroes of this polynomial are given by x-1=0 and x-3=0<br />

x=1 and x=3<br />

Sum of zeroes = 1+3 = 4 = -(-8)/2 = -<br />

Coefficient of x<br />

coefficient of x²<br />

Product of zeroes =( 1) (3) = 3 = 6/2 =<br />

Coefficient term<br />

coefficient of x²<br />

MATHEMATICS UNIT - 2<br />

11


Now, let us learn to write a quadratic polynomial when sum and product of its zeroes is<br />

given.<br />

Remember: A quadratic polynomial whose sum of zeroes is S and product of zeroes is P<br />

is given by x² -Sx +P<br />

Example: Write a quadratic polynomial whose sum of zeroes is 5 and product of zeroes<br />

is 10<br />

Here Sum of zeroes = 5 and Product of zeroes= 10<br />

Using the formula, required polynomial is x² - 5x + 10<br />

Note: If αand βare zeroes of a quadratic polynomial then the required polynomial is<br />

given by (x- α) (x- β)<br />

2.5 Geometric Representation of Zero of a Polynomial<br />

What are the x-intercept and y-intercept of a graph?<br />

(0,b)<br />

y-intercept<br />

(-a, 0)<br />

x-intercept<br />

The x-intercept is that value of x where the graph crosses or touches the x-axis. At the x-<br />

intercept on the x-axis y = 0.<br />

The y-intercept is that value of y where the graph crosses the y-axis. At the y-intercept,<br />

x = 0.<br />

What is the relationship between the zero of a polynomial and the x-intercepts of its<br />

graph?<br />

The zeroes are the x-intercepts!<br />

12<br />

MATHEMATICS UNIT - 2


The zeroes of x² - x - 6 are -2 and 3. Therefore, the graph of y = x² - x - 6 will cross the<br />

x - axis at -2 and 3.<br />

The graph of a linear polynomial of the form ax + b, a not equal to zero is a straight line<br />

which intersects the x-axis at exactly one point. The value of x coordinates of the point<br />

where the line meets x- axis is zero of the polynomial.<br />

Graph of a linear Polynomials<br />

Consider the following graph<br />

MATHEMATICS UNIT - 2<br />

13


This is a graph of linear polynomial 2x+3. It intersects the x-axis at point (-1.5, 0).<br />

So, the linear polynomial 2x+3 has one zero, given by -1.5 (x-coordinate of point where<br />

line cuts the x-axis)<br />

Exploring graphs of Quadratic polynomial<br />

2<br />

• A quadratic polynomial is given by ax +bx+c, a ≠0, a,b,c, are real numbers.<br />

• The degree of a quadratic polynomial is 2.<br />

• Graph of a quadratic polynomial is a parabola.<br />

• There are at most two zeroes of a quadratic polynomial.<br />

Observe the following graphs.<br />

This is a graph of a quadratic polynomial which do not intersect the x- axis at any of the<br />

points, so there is no zero of this polynomial.<br />

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In the second graph, the curve touches the x-axis at one point, so it has 1 zero. What is<br />

that zero?<br />

In the following graph, the curve cuts the x-axis at two points, so the given quadratic<br />

polynomial has two zeroes. Write the two zeroes from the graph.<br />

Note: The zero of a quadratic polynomial is the value of x- coordinate of a<br />

point where the graph of the polynomial cuts the x-axis. It has at most 2 zeroes<br />

MATHEMATICS UNIT - 2<br />

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2.6 Observing the number of zeroes of a polynomial from its graph<br />

(i)<br />

The graphs of y = p(x) are given in following figure, for some polynomials p(x). Find the<br />

number of zeroes of p(x), in each case.<br />

(ii)<br />

Observation: The graph of y=p(x) does not intersect the x-axis at any point. This means<br />

it has no zero.<br />

(iii)<br />

Observation: The graph of y=p(x) intersects the x-axis at one point. This means it has<br />

one zero.<br />

Observation: The graph of y=p(x) intersect the x-axis at three points. This means it has 3<br />

zeros.<br />

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(iv)<br />

Observation: The graph of y=p(x) intersect the x-axis at two points. This means it has 2<br />

zeros.<br />

(v)<br />

Observation: The graph of y=p(x) intersect the x-axis at four points. This means it has 4<br />

zeros.<br />

(vi)<br />

Observation: The graph of y=p(x) intersect the x-axis at three points. This means it has 3<br />

zeros.<br />

MATHEMATICS UNIT - 2<br />

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2.7 Division of polynomials<br />

In previous classes students have learnt the division of integers. Also, they have the<br />

knowledge of Euclid's division lemma i.e. dividend = divisor x quotient + remainder.<br />

Let us see the process of division of polynomials.<br />

First let us divide 5x³ - x³ + 6 by x - 4.<br />

We write it as shown below<br />

x - 4 5x³ - x² + 0x + 6<br />

We need to have the terms written down with the exponents in decreasing order and to<br />

make sure we don't make any mistakes we add in any missing terms with a zero<br />

coefficient.<br />

Now we we need to multiply x - 4 to get the first term in first polynomial. In this case<br />

that is 5x². So multiply x - 4 by 5x² and subtract the results from the first polynomial.<br />

5x²<br />

x - 4 5x³ - x² + 0x + 6<br />

- (5x³ - 20x²)<br />

19x² + 0x + 6<br />

The new polynomial is called the remainder. We continue the process until the degree<br />

of the remainder is less than the degree of the divisor, which is x - 4 in this case. So, we<br />

need to continue until the degree of the remainder is less than 1.<br />

Recall that the degree of a polynomial is the highest exponent in the polynomial. Also,<br />

recall that a constant is thought of as a polynomial of degree zero. Therefore, we'll need<br />

to continue until we get a constant in this case.<br />

Here is the rest of the work for this example.<br />

5x² + 19x + 76<br />

x - 4 5x³ - x² + 0x + 6<br />

- (5x³ - 20x²)<br />

19x² + 0x + 6<br />

- (19x² - 76x)<br />

76 + 6<br />

- (76x - 304)<br />

310<br />

18<br />

MATHEMATICS UNIT - 2


What is division algorithm for polynomials?<br />

Division algorithm states that : Given a polynomial P(x) with degree at least 1 and any<br />

number R there is another polynomial Q(x), called the quotient, with degree one less<br />

than the degree of P(x) and a number R, called the remainder, such that,<br />

P (x) = (x - r) Q (x) + R<br />

Division algorithm: Dividend = Divisor x Quotient + Remainder<br />

Example Divide x³ -3x² +5x -3 by x² -2<br />

(I) p(x) = x³ - 3x² + 5x - 3<br />

q(x) = x² - 2<br />

x - 3<br />

x² - 2 x³ - 3x² + 5x - 3<br />

x³ - 2x<br />

- +<br />

- 3x² + 7x - 3<br />

- 3x² +6<br />

+ -<br />

7x - 9<br />

Quotient = x - 3<br />

Remainder = 7x - 9<br />

2 4 3 2<br />

Example To check whether x +3x+1 is a factor of 3x + 5x -7x +2x+2.<br />

3x² - 4x + 2<br />

4<br />

x² + 3x + 1 3x + 5x³ - 7x² + 2x + 2<br />

4<br />

3x + 9x³ + 3x²<br />

- - -<br />

- 4x³ - 10x² + 2x + 2<br />

- 4x³ - 12x² - 4x<br />

+ + +<br />

2x² + 6x + 2<br />

2x² + 6x + 2<br />

0<br />

MATHEMATICS UNIT - 2<br />

19


Since the remainder is 0,<br />

4<br />

Hence, x² + 3x + 1 is a factor of 3x + 5x³ - 7x² + 2x + 2<br />

Discussion: How many zeroes a cubic polynomial has? Yes, you are right. A cubic<br />

polynomial has at most 3 zeroes.<br />

You have learnt how to find rational zero of a cubic polynomial. For the problem<br />

discussed earlier we were able to found one zero and mentioned that rest of the zeroes<br />

we will be able to find after learning Division Algorithm. Now, we will use the division<br />

of polynomials process to do the same.<br />

Example: If one zero of a cubic polynomial x³ - 3x² - x+3 is 1, then find the other zeroes.<br />

In this problem, it is given that one zero is 1, this means (x-1) is a factor of given<br />

polynomial.<br />

We will divide the given polynomial by (x-1).<br />

On dividing we get x³ - 3x² - x+3 = (x-1)(x²-2x-3) +0<br />

But x² - 2x - 3 can be factorised as (x+1) (x-3)<br />

.: x³ - 3x² - x + 3 = (x-1) (x²-2x-3) + 0<br />

= (x-1) (x+1) (x-3) + 0<br />

⇒Factors of the polynomial x³ - 3x² - x + 3<br />

are (x-1) (x+1) (x-3)<br />

Note : Find all zeroes of polynomial x³ - 3x + 2 = 0<br />

You already know that one zero of this polynomial is 1.<br />

20<br />

MATHEMATICS UNIT - 2


Teachers'<br />

Support<br />

Material<br />

MATHEMATICS UNIT - 2<br />

21


2.8 Activity 1- Warm up (W1)<br />

Description: This is a starter activity to engage students in learning. Show the image<br />

given below and ask the students to read the words one by one. Tell them we will play a<br />

game using these terms.<br />

Pre Preparation:<br />

Prepare paper slips on which various terms and<br />

statements are written. Put them in a bowl and<br />

ask each student to pick up one slip.<br />

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MATHEMATICS UNIT - 2


monomial<br />

A binomial having degree 4<br />

A trinomial having degree 4<br />

A constant polynomial<br />

A cubic polynomial<br />

A quadratic polynomial<br />

A trinomial whose constant<br />

term is 1<br />

Execution: Each student will have to say one sentence about the written terms or give<br />

examples in support of statement on the slip.<br />

MATHEMATICS UNIT - 2<br />

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2.9 Activity 2- Warm up (W2)<br />

Specific Objectives:<br />

• To explore an algebraic expression and find whether it is a polynomial or not?<br />

• To find If the given expression is a polynomial then it is a polynomial in one variable<br />

or not?<br />

• To find If the given expression is a polynomial then observe its degree and count the<br />

number of terms<br />

• To name the given polynomial according to its degree.<br />

• To name the given polynomial according to the number of terms in it.<br />

Description: This is a brainstorming warm up activity. Write any algebraic<br />

expression on the board. Students will be asked to comment on the expression. They<br />

will brainstorm on various aspects<br />

• Is it a polynomial? Why and Why not?<br />

• If yes, then what is the degree? What will you call it on the basis of degree?<br />

• How many terms are there? What will you call it on the basis of number of terms?<br />

• What are the coefficients of various terms?<br />

Pre preparation:<br />

Make a list of various algebraic polynomials.<br />

Some of them are not to be polynomials.<br />

Prepare a list of points for brainstorming.<br />

Terms: Monomial, Binomial, Trinomial, Polynomial, Degree, Quadratic polynomial,<br />

Cubic Polynomial, Coefficients<br />

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Execution :<br />

Consider the given algebraic expression<br />

4x³ + 3x² - 5x - 6<br />

Ask the students to write observations on the following statements<br />

1. The given algebraic expression is a polynomial<br />

2. It is a polynomial in one variable<br />

3. The coefficient of x is 5<br />

4. Its constant term is 6<br />

5. Its degree is 5<br />

6. It is a cubic polynomial<br />

7. It has 4 terms<br />

8. The coefficient of x² is 3<br />

9. If we remove -5x term then it will become a trinomial<br />

10. If we remove any of one term, then it will become a trinomial<br />

11. If we add one more term having degree 4 then it will become a polynomial of degree 4.<br />

MATHEMATICS UNIT - 2<br />

25


2.10 Activity 3 Pre Content (P1)<br />

Specific Objectives:<br />

• To recall the concept of value of a polynomial at a given point<br />

• To practice to find the value of a polynomial at a given point<br />

• To revise the concept of zero of a linear polynomial<br />

Description: Students have studied in class 9 to find the value of a polynomial at a given<br />

point. Also, they have learnt to calculate zeroes of a linear polynomial. For example, to<br />

calculate the zero of linear polynomial p(x) = 3x -2, put 3x-2 = 0. So, the zero of p(x) = 3x -<br />

2 will be 2/3.<br />

Prepare a worksheet for students for testing the previous knowledge based on two<br />

concepts.<br />

2 Finding the value of a polynomial at a given point<br />

3 Zeroes of a linear polynomial<br />

Execution: Ask the students to solve the worksheet. Discuss orally the important<br />

points. Let students speak the method of finding zero of a linear polynomial.<br />

Specific Objectives:<br />

Description:<br />

2.11 Activity 4 Content Worksheet (CW1)<br />

• to be able to write linear and quadratic polynomials<br />

• to be able to find the zeroes of a linear polynomial<br />

• to be able to find the zeroes of a quadratic polynomial by splitting the middle term<br />

After learning to find the zeroes of a polynomial, students will be provided with<br />

content worksheet CW1. It is a 20 minutes task in which students will use their<br />

knowledge and solve the exercise given in the worksheet.<br />

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Follow up:<br />

Revise important points learnt till now. Ask the students to make a mind map.<br />

Specific Objectives:<br />

2.12 Activity5 Content Worksheet (CW2)<br />

• To find the zeroes of a quadratic polynomial and verify the relationship between zeroes<br />

and coefficients<br />

• To write a quadratic polynomial when its zeroes are given<br />

• To write a quadratic polynomial when sum and product of its zeroes are given<br />

Description: After learning how to find the zeroes of a quadratic polynomial, students<br />

will be given a worksheet on finding a relationship between zeroes and coefficients of a<br />

quadratic polynomial. Students will use the knowledge of splitting the middle term<br />

concept and find the zeroes of a given quadratic polynomial. They will further verify<br />

the relationship between zeroes and coefficients of the polynomial.<br />

Specific Objectives:<br />

2.13 Activity 6 Content Worksheet (CW3)<br />

• To practice the skill of drawing graphs of a linear polynomial on a graph paper<br />

• To observe the graph of a polynomial and tell the number of zeroes<br />

• To tell the value of zero(s) of a polynomial from its graph<br />

Description: Teacher will ask the students to write a linear polynomial and draw its<br />

graph. Each student will make the table of values and plot the points on a graph paper.<br />

Students will be then asked to observe the points where the graph intersects the x- axis<br />

(if any).<br />

Let students verify that the abscissa of the point where the graph intersects the x- axis is<br />

the required zero of the given polynomial.<br />

MATHEMATICS UNIT - 2<br />

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2.14 Activity 7 Content Worksheet (CW4)<br />

Specific Objectives:<br />

To observe the number of zeroes of a polynomial from its graph.<br />

Description:<br />

Students will be asked to observe the graphs of polynomials. They will be asked.<br />

(i) Is the graph intersecting x-axis at any point?<br />

(ii) At, how many points, the graph in intersecting x-axis?<br />

Hence, how much zeroes, the polynomials have?<br />

Specific Objectives:<br />

Description<br />

2.15 Activity 8 Content Worksheet (CW5)<br />

To divide a polynomials of degree more than 1 by a linear polynomial.<br />

To find the quotient and the remainder.<br />

To understand the division algorithm to establish that<br />

Dividend = Divisor x Quotient + Remainder.<br />

Students will be given two polynomials p(x) and g(x) and will be asked.<br />

1. Which of these polynomials can be divided by the other?<br />

2. What will be the degree of quotient?<br />

3. What will be the degree of the remainder?<br />

Take different examples of p(x) and g(x) and find q(x), the quotient and r(x), the<br />

remainder.<br />

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2.16 Useful Resources<br />

(i)<br />

http://www.sosmath.com/algebra/factor/fac01/fac01.html<br />

(On this web page the process of long division of polynomials is explained step by step)<br />

(ii)<br />

http://www.mathsisfun.com/algebra/polynomials-division-long.html<br />

(On this web page, some videos are inserted for the explanation of long division in<br />

polynomials)<br />

Useful Videos<br />

i. Note: If the students find problem in splitting the middle term of a quadratic<br />

polynomial then they may watch Video: Splitting the middle term<br />

http://www.youtube.com/watch?v=07IenNnS3Xs<br />

ii. http://www.youtube.com/watch?v=FsotIB0Usvw<br />

iii.<br />

Dividing a quadratic polynomial by a linear polynomial<br />

http://www.youtube.com/watch?v=l6_ghhd7kwQ&feature=relmfu<br />

MATHEMATICS UNIT - 2<br />

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Students'<br />

Support<br />

Material<br />

MATHEMATICS UNIT - 2<br />

31


Student's Worksheet-1<br />

Warm up (W1)<br />

Name of student______________________________________<br />

Date__________________<br />

Consider the given algebraic expression<br />

3 2<br />

4x + 3x - 5x - 6<br />

Give your comments on the following statements:<br />

• The coefficient of x is 5<br />

_____________________________________________________________<br />

• This is a polynomial<br />

_____________________________________________________________<br />

• Its constant term is -6<br />

_____________________________________________________________<br />

• Its degree is 5<br />

_____________________________________________________________<br />

• It is a cubic polynomial.<br />

_____________________________________________________________<br />

• It has 4 terms<br />

_____________________________________________________________<br />

• The coefficient of x² is 3<br />

_____________________________________________________________<br />

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• If we remove -5x term then it will become a trinomial<br />

_____________________________________________________________<br />

• If we remove any of one term, then it will become a trinomial<br />

_____________________________________________________________<br />

• If we add one more term having degree 4 then it will become a polynomial of degree 4.<br />

_____________________________________________________________<br />

Student's Worksheet - 1A<br />

Warm up (W2)<br />

Name of student________________________________________<br />

Date__________________<br />

Understanding of terms along with their meaning<br />

MATHEMATICS UNIT - 2<br />

33


Self Assessment Rubric - 1<br />

Term<br />

Polynomial<br />

Monomial<br />

Binomial<br />

Trinomial<br />

Linear Polynomial<br />

Quadratic Polynomial<br />

Cubic Polynomial<br />

Quartic Polynomial<br />

Coefficient of terms<br />

Degree of polynomial<br />

Knows the meaning Aware of the term but<br />

do not know the<br />

meaning<br />

Do not know<br />

what it is?<br />

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Student's Worksheet-2<br />

Pre content (P1)<br />

Name of student_________________________________________<br />

Date___________________<br />

Choose the correct answer.<br />

1. The zero of the polynomial P(x) = x+5 is<br />

(i) 5 (ii) -5 (iii) 0 (iv) 1<br />

3<br />

2. The remainder when x +1 is divided by x+1 is<br />

(i) 1 (ii) 2 (iii) -1 (iv) 0<br />

3 2<br />

3. If x-1 is a factor of 4x +3x -4x+K, then value of K is<br />

(i) 3 (ii) -3 (iii) 0 (iv) -2<br />

2<br />

4. The value of the polynomial 5x-4x +3 at x= -1 is<br />

(i) 6 (ii) -1 (iii) -6 (iv) 3<br />

Fill the table given below<br />

Polynomial<br />

3<br />

P(x)= 4x -5x+2<br />

2<br />

P(t) = 5t +3t -8<br />

Value<br />

P(2)=<br />

P(1)=<br />

P(y)=7y² + 2u - 1 P(½) =<br />

4 3<br />

P(r) = 4r + 7y + 2 P(0) =<br />

P(y) = 1 - ½y³ P(-1) =<br />

P(r)= ar³ + 1 P(1) =<br />

MATHEMATICS UNIT - 2<br />

35


Self Assessment Rubric 2<br />

Student's Worksheet-3<br />

Pre Content (P1)<br />

Name of student____________________________<br />

Date__________________<br />

Rate your knowledge according to the given scale.<br />

Skill<br />

Able to find the zero of a<br />

linear polynomial<br />

Able to apply Remainder<br />

theorem<br />

Able to apply factor<br />

theorem<br />

Able to find value of a<br />

polynomial at a given point<br />

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Student's Worksheet-4<br />

Content Worksheet (CW1)<br />

Name of student_____________________________________________ Date______________<br />

1. Write two examples each of a linear polynomial and a quadratic polynomial.<br />

Type of polynomial<br />

Examples<br />

Linear<br />

Quadratic<br />

2. Find the zeroes of following linear polynomials.<br />

a) P(x) = 7x +3<br />

b) Q(t) = 3t -2<br />

3. Take any three linear polynomials. Find the zeroes. How many zeroes a linear<br />

polynomial has?<br />

___________________________________________________________________________<br />

___________________________________________________________________________<br />

___________________________________________________________________________<br />

___________________________________________________________________________<br />

___________________________________________________________________________<br />

___________________________________________________________________________<br />

MATHEMATICS UNIT - 2<br />

37


4. Factorise the following quadratic polynomials using the splitting the middle term. Find<br />

the zeroes.<br />

2<br />

a) 5x -6x + 1<br />

2<br />

b) t -2x-8<br />

2<br />

c) 4m -4m+1<br />

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Self Assessment Rubric 3<br />

Student's Worksheet-5<br />

Content Worksheet (CW1)<br />

Name of student_________________________________________<br />

Date__________________<br />

Rate your knowledge according to the given scale.<br />

Skill<br />

Able to write a linear/<br />

quadratic/cubic polynomial<br />

Able to find zeroes of a<br />

linear polynomial<br />

Able to find zeroes of a<br />

quadratic polynomial<br />

MATHEMATICS UNIT - 2<br />

39


Student's Worksheet-6<br />

Content Worksheet (CW2)<br />

Name of student_____________________________________________ Date______________<br />

Assignment:<br />

Q1<br />

Find the zeroes of the following quadratic polynomials and verify the relationship<br />

between zeroes and coefficients.<br />

(a) x² + 8x + 12<br />

(b) x² + 3x - 4<br />

(c) x² - 7x + 10<br />

(d) y² - 4<br />

Q2<br />

Q3<br />

Q4<br />

Find a quadratic polynomial each with the given numbers as the sum and product of its<br />

zeroes respectively:<br />

3 3<br />

(a) 3 and 4 (b) -2 and (c) - and 0 (d) -2 and 3<br />

2 2<br />

Find a quadratic polynomial with -1 as zero.<br />

Find a cubic polynomial with zeroes as 2, -2½.<br />

Q5 Find a cubic polynomial with zeroes 1, 1, 2.<br />

Q6 Find a cubic polynomial with zeroes -1, -1, -1.<br />

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Self Assessment Rubric 4<br />

Student's Worksheet-7<br />

Content Worksheet (CW2)<br />

Name of student_________________________________________<br />

Date__________________<br />

Rate your knowledge according to the given scale.<br />

Skill<br />

Able to verify the relation<br />

b e t w e e n z e r o e s a n d<br />

coefficient<br />

Able to write a quadratic<br />

polynomial when its zeroes<br />

are given<br />

Able to write a quadratic<br />

polynomial when sum and<br />

product of its zeroes is<br />

given<br />

MATHEMATICS UNIT - 2<br />

41


Student's Worksheet-8<br />

Content Worksheet (CW3)<br />

Name of student_________________________________________<br />

Date__________________<br />

1. Draw the graph of y = 2x + 5.<br />

X<br />

Y<br />

Find the points where the straight line cuts the x- axis and the y- axis.<br />

The straight line cuts the x- axis at ……………………..<br />

The straight line cuts the y- axis at …………………….<br />

Now, to get zero, 2x + 5 = 0<br />

⇒x = -5/2<br />

Observe that the graph of y = 2x + 5 intersects the x- axis at the point ( -5/2 , 0).<br />

Note: The zero of the polynomial 2x + 5 is the x-coordinate of the point i.e. - 5/2 where the<br />

graph of y = 2x + 5 intersects the x-axis.<br />

2. Draw the graph of following linear polynomials. Find the zero from the graph. How<br />

many zeroes a linear polynomial has? Verify you answer.<br />

a) 5x-3<br />

b) 2x+6<br />

c) 6x-2<br />

d) 2x-4<br />

42<br />

MATHEMATICS UNIT - 2


3. The graph of y = p(x) are drawn below. Mark the number of zeros in each case:<br />

a) b)<br />

c) d)<br />

e) f)<br />

MATHEMATICS UNIT - 2<br />

43


Self Assessment Rubric 5<br />

Student's Worksheet-9<br />

Content Worksheet (CW3)<br />

Name of student_________________________________________<br />

Date__________________<br />

Rate your knowledge according to the given scale.<br />

Skill<br />

Able to draw the graph of a<br />

linear polynomial<br />

Able to find zeroes of a<br />

linear polynomial from its<br />

graph<br />

Able to find zeroes of a<br />

polynomial from its graph<br />

44<br />

MATHEMATICS UNIT - 2


Student's Worksheet-10<br />

Content Worksheet (CW4)<br />

Name of student_________________________________________<br />

Date__________________<br />

• A polynomial of degree n has at most n zeroes.<br />

• Geometrically the zeroes of a polynomial are x coordinates of points where the graph of<br />

polynomial cuts/touches the x-axis.<br />

The zeroes of a polynomial p(x) are precisely the x-coordinates of the points, where the<br />

graph of y = p(x) intersects the x -axis.<br />

Observe the given graphs and fill the respective rows.<br />

S. No. Graph of y = f(x)<br />

1. Graph of a<br />

linear<br />

polynomial<br />

Number of Zeroes<br />

Zeroes<br />

2. Graph of a<br />

quadratic<br />

polynomial<br />

MATHEMATICS UNIT - 2<br />

45


S. No. Graph of y = f(x)<br />

3. Graph of a<br />

quadratic<br />

polynomials<br />

Number of Zeroes<br />

Zeroes<br />

4. Graph of a<br />

quadratic<br />

polynomial<br />

46<br />

MATHEMATICS UNIT - 2


Self Assessment Rubric 6<br />

Student's Worksheet-11<br />

Content Worksheet (CW4)<br />

Name of student_________________________________________<br />

Date__________________<br />

Rate your knowledge according to the given scale.<br />

Skill<br />

Able to find number of<br />

zeroes of a polynomial<br />

from its graph<br />

Able to find zeroes of a<br />

polynomial from its graph<br />

MATHEMATICS UNIT - 2<br />

47


Student's Worksheet-12<br />

Content Worksheet (CW5)<br />

Name of student_________________________________________<br />

Date__________________<br />

Exercise:<br />

1. Apply the division algorithm to find the quotient and the remainder on dividing p(x) by<br />

q(x)<br />

3 2<br />

I. p(x)= x +15x +48x, q(x)= x+8<br />

3 2<br />

ii. p(x) = 14x -5x +9x-1, q(x) = 2x-1<br />

2. Check whether the first polynomial is a factor of the second polynomial by dividing the<br />

second polynomial by the first polynomial:<br />

2<br />

a) (x-1), 5x -3x+2<br />

2<br />

b) (x+1), 2x +5x+3<br />

3 2<br />

3. On dividing x -3x +5x -3 by a polynomial g(x), the quotient is (x-3) and the remainder is<br />

(7x-9). Find g(x). Write the formula used.<br />

3 2<br />

4. Find the value of a and b so that 1, -2 are the zeroes of the polynomial x + 10x + ax + b.<br />

5. Divide the polynomial p(x) by q(x) in each of the following cases and find the quotient<br />

and remainder:<br />

3<br />

a) p(x) = 7x - 5x + 8 q(x) = x - ½<br />

b) p(x) = 6x² - 5x² + 4x + 3 q(x) = 4x² + 1<br />

c) p(x) = 16x³ - 4x² + 2x + 7 q(x) = 2x - 1<br />

48<br />

MATHEMATICS UNIT - 2


Self Assessment Rubric 7<br />

Student's Worksheet-13<br />

Content Worksheet (CW5)<br />

Name of student_________________________________________<br />

Date__________________<br />

Rate your knowledge according to the given scale.<br />

Skill<br />

Able to divide a quadratic polynomial by<br />

a linear polynomial<br />

Able to divide a cubic polynomial by a<br />

linear polynomial<br />

Able to divide a cubic polynomial by a<br />

quadratic polynomial<br />

Able to verify division algorithm for<br />

polynomials<br />

Able to find zeroes of a polynomial using<br />

division algorithm<br />

MATHEMATICS UNIT - 2<br />

49


Student's Worksheet-14<br />

Post Content Worksheet (PCW1)<br />

1. Fill in the blanks<br />

i. Polynomials of degrees 1, 2 and 3 are called………….. , …………….. And cubic<br />

polynomials respectively.<br />

2<br />

ii. A…………… polynomial in x with real coefficients is of the form ax + bx + c, where<br />

a, b,c are real numbers with a?0.<br />

iii. The zeroes of a polynomial p(x) are precisely the …………………… of the points,<br />

where the graph of y = p(x) intersects the x -axis.<br />

iv. A quadratic polynomial can have at most ………….. zeroes and a cubic polynomial<br />

can have at most …………… zeroes.<br />

v. If and βare the zeroes of the quadratic polynomial ax² + bx + c, then<br />

a. α+ β= …………… and αβ= …………………<br />

vi. The division algorithm states that given any polynomial p(x) and any non-zero<br />

polynomial g(x), there are polynomials q(x) and r(x) such that<br />

p(x) = g(x) q(x) + r(x),where r(x) = 0 or degree r(x) ……………. degree g(x).<br />

2. Find the quadratic polynomial, the sum and product of whose zeroes are<br />

1) ½, -2<br />

2) -3, -7<br />

3) 5+√3 & 5-√2<br />

3. Find the zeroes of the quadratic polynomial p(x) =t ² - 15<br />

4. How many maximum zeroes can a polynomial of degree two has?<br />

5. What is the zero of the polynomial ax + b=0, a≠0?<br />

6. Find the sum & the product of the zeroes of the polynomial 6x²-x-2.<br />

50<br />

MATHEMATICS UNIT - 2


7. Give examples of polynomials f(x), g(x), q(x) & r(x) which satisfy the division algorithm<br />

1) deg r(x)=0<br />

2) deg f(x)=deg q(x)=2<br />

8. Find the quadratic polynomial whose one zero is 5 & product of zeroes is 30.<br />

9. The linear polynomial ax + b, a ? 0, has exactly one zero, namely, the__________ of the<br />

point where the graph of y = ax + b intersects the x-axis.<br />

10. Divide the polynomial p(x) by the polynomial g(x) and find the quotient and remainder<br />

in each of the following:<br />

3 2 2<br />

(i ) p(x)=x -3x +5x-3,g(x)=x -2<br />

3 2 2<br />

(ii) p(x) = x - 3x + 4x + 5, g(x) = x + 1 - x<br />

Student's Worksheet-15<br />

Post Content Worksheet (PCW2)<br />

1. Express the polynomial given in column I in the form of and match with the<br />

coefficients of their terms in Column II<br />

COLUMN I<br />

COLUMN II<br />

x² + 6x a = 1 b = 0 c = 6<br />

x² + 6 a = 0 b = 1 c = 6<br />

x+ 6 a = 1 b = 6 c = 0<br />

2. Match the polynomials in column I with their zeros in column II<br />

COLUMN I<br />

COLUMN II<br />

x² - 5x - 6 α= -6 β= 1<br />

x² + 5x - 6 α= -6 β= 1<br />

x² - 7x + 6 α= -6 β= 1<br />

x² + 7x + 6 α= -6 β= 1<br />

MATHEMATICS UNIT - 2<br />

51


3. Fill in the appropriate boxes:<br />

Dividend Divisor Quotient Remainder<br />

x² + 3x + 4 x + 1 2<br />

x² + 7x + 7 x + 5 1<br />

x² - 5x + 6 x - 1 -2<br />

x² - 3x - 12 x - 5 x + 2<br />

4. Fill in the blanks:-<br />

i) The zeroes of the polynomial ________________ are -3 and -4.<br />

ii) The remainder is ________________ when x³ + 5x² + 3x - 2 is divided by x + 1 .<br />

iii)<br />

If the zeroes of the polynomial are 5 and 6 then the co-efficient of is _________.<br />

iv)<br />

If the zeroes of the polynomial are opposite in sign then the co-efficient of x is<br />

______.<br />

v) The sum and product of zeroes of the polynomial ______________ are -2 and<br />

vi)<br />

The polynomial x² + 10x + 25 has______________ roots.<br />

-3<br />

2<br />

vii)<br />

If a polynomial of degree five is divided by a quadratic polynomial then the<br />

degree of the quotient polynomial is _______________.<br />

viii) The quotient polynomial is ______________ if the two zeroes of the polynomial<br />

x³ + 5x² - 4x + 5 are 2 and -2.<br />

52<br />

MATHEMATICS UNIT - 2


Assessment guidance plan for teachers<br />

With each task in student support material a self -assessment rubric is attached for students.<br />

Discuss with the students how each rubric can help them to keep in tune their own progress.<br />

These rubrics are meant to develop the learner as the self motivated learner.<br />

To assess the students' progress by teacher two types of rubrics are suggested below, one is for<br />

formative assessment and one is for summative assessment.<br />

Suggestive Rubric for Formative Assessment (exemplary)<br />

Parameter<br />

Mastered<br />

Developing<br />

Needs motivation<br />

Needs personal<br />

attention<br />

Factorisatio<br />

n of<br />

polynomial<br />

Able to factorise<br />

quadratic<br />

polynomial by<br />

splitting of middle<br />

term<br />

Able to factorise<br />

quadratic<br />

polynomial using<br />

formula<br />

Able to find atleast<br />

one factor using<br />

leading coefficient<br />

and constant term<br />

Able to use division<br />

of polynomials to<br />

find other factor<br />

Able to find out the<br />

factors of cubic<br />

polynomial by<br />

grouping them<br />

Able to find out<br />

atleast one factor by<br />

use of leading<br />

coefficients and<br />

constant term<br />

Able to find other<br />

factors using<br />

division of<br />

polynomials and<br />

repeating the same<br />

procedure to get all<br />

factors<br />

From above rubric it is very clear that<br />

Able to factorise<br />

quadratic<br />

polynomial by<br />

splitting of middle<br />

term<br />

Able to factorise<br />

quadratic<br />

polynomial using<br />

formula<br />

Able to find atleast<br />

one factor using<br />

leading coefficient<br />

and constant term<br />

Able to use<br />

division of<br />

polynomials to find<br />

other factor<br />

Able to find out the<br />

factors of cubic<br />

polynomial by<br />

grouping them<br />

Able to find out<br />

atleast one factor<br />

by use of leading<br />

coefficients and<br />

constant term<br />

Able to find other<br />

factors using<br />

division of<br />

polynomials but<br />

not able to repeat<br />

the same procedure<br />

to get all factors<br />

Able to factorise<br />

quadratic<br />

polynomial by<br />

splitting of middle<br />

term<br />

Not able to<br />

factorise quadratic<br />

polynomial using<br />

formula<br />

Able to find atleast<br />

one factor using<br />

leading coefficient<br />

and constant term<br />

Not able to use<br />

division of<br />

polynomials to<br />

find other factor<br />

Not able to find<br />

out the factors of<br />

cubic polynomial<br />

by grouping them<br />

Able to find out<br />

atleast one factor<br />

by use of leading<br />

coefficients and<br />

constant term<br />

Not able to find<br />

other factors using<br />

division of<br />

polynomials and<br />

repeating the same<br />

procedure to get<br />

all factors<br />

Not able to factorise<br />

quadratic<br />

polynomial by<br />

splitting of middle<br />

term<br />

Not able to factorise<br />

quadratic<br />

polynomial using<br />

formula<br />

Not able to find<br />

atleast one factor<br />

using leading<br />

coefficient and<br />

constant term<br />

Not able to use<br />

division of<br />

polynomials to find<br />

other factor<br />

Not able to find out<br />

the factors of cubic<br />

polynomial by<br />

grouping them<br />

Not able to find out<br />

atleast one factor by<br />

use of leading<br />

coefficients and<br />

constant term<br />

Not able to find<br />

other factors using<br />

division of<br />

polynomials and<br />

repeating the same<br />

procedure to get all<br />

factors<br />

MATHEMATICS UNIT - 2<br />

53


•<br />

•<br />

•<br />

•<br />

Learner requiring personal attention is poor in concepts and requires the<br />

training of basic concepts before moving further.<br />

Learner requiring motivation is able to do a lot but stuck up with division of<br />

polynomials. He can be trained by peer trainers or by doing remedial<br />

worksheets.<br />

Learner who is developing is able to almost all type of problems but needs more<br />

practice to solve cubic polynomials and to understand how the procedure can be<br />

repeated.<br />

Learner who has mastered the skill of factorisation of polynomials can be given<br />

higher order polynomials for factorisation.<br />

Teachers' Rubric for Summative Assessment of the <strong>Unit</strong><br />

Parameter<br />

Factorisation of<br />

polynomial<br />

algebraically<br />

Finding zeroes<br />

of polynomial<br />

Division<br />

algorithm<br />

5<br />

• Able to factorise<br />

quadratic polynomial<br />

• Able to factorise cubic<br />

polynomial<br />

• Able to factorise<br />

biquadratic polynomial<br />

• Able to find zeroes of<br />

polynomial by<br />

factorising it.<br />

• Able to read zeroes<br />

from graph of<br />

polynomial<br />

• Able to find zeroes of<br />

polynomial using the<br />

relation between<br />

coefficients of<br />

polynomial and its<br />

zeroes.<br />

• Able to divide linear<br />

polynomial by a linear<br />

polynomial.<br />

• Able to divide<br />

quadratic polynomial<br />

by a linear polynomial.<br />

• Able to divide cubic<br />

polynomial by a linear<br />

polynomial.<br />

• Able to divide cubic<br />

polynomial by a<br />

quadratic polynomial.<br />

1<br />

• Not able to factorise<br />

quadratic polynomial<br />

• Not able to factorise<br />

cubic polynomial<br />

• Not able to factorise<br />

biquadratic polynomial<br />

• Not able to find zeroes of<br />

polynomial by<br />

factorising it.<br />

• Not able to read zeroes<br />

from graph of<br />

polynomial<br />

• Not able to find zeroes of<br />

polynomial using the<br />

relation between<br />

coefficients of<br />

polynomial and its<br />

zeroes.<br />

• Not able to divide linear<br />

polynomial by a linear<br />

polynomial.<br />

• Not able to divide<br />

quadratic polynomial by<br />

a linear polynomial.<br />

• Not able to divide cubic<br />

polynomial by a linear<br />

polynomial.<br />

• Not able to divide<br />

cubic polynomial by a<br />

quadratic polynomial.<br />

54<br />

MATHEMATICS UNIT - 2


CENTRAL BOARD OF SECONDARY EDUCATION<br />

Shiksha Kendra, 2, Community Centre, Preet Vihar,<br />

Delhi-110 092 India

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