Date post: | 15-Jul-2015 |
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Introduction :
A polynomial is an expression of finite length constructed from
variables and constants, using only the operations of addition,
subtraction, multiplication, and non-negative, whole-number exponents.
Polynomials appear in a wide variety.
Let x be a variable n, be a positive integer and as, a1,a2,….an be constants (real nos.)
Then, f(x) = anxn+ an-1xn-1+….+a1x+xo
anxn,an-1xn-1,….a1x and ao are known as the terms of the polynomial.
an,an-1,an-2,….a1 and ao are their coefficients.
For example:
• p(x) = 3x – 2 is a polynomial in variable x.
• q(x) = 3y2 – 2y + 4 is a polynomial in variable y.
• f(u) = 1/2u3 – 3u2 + 2u – 4 is a polynomial in variable u.
NOTENOTE: 2x2 – 3√x + 5, 1/x2 – 2x +5 , 2x3 – 3/x +4 are not polynomials.
Cont…
The exponent of the highest degree term in a polynomial is known as its
degree.
For example: f(x) = 3x + ½ is a polynomial in the variable x of degree 1. g(y) = 2y2 – 3/2y + 7 is a polynomial in the variable y of degree 2. p(x) = 5x3 – 3x2 + x – 1/√2 is a polynomial in the variable x of degree 3. q(u) = 9u5 – 2/3u4 + u2 – ½ is a polynomial in the variable u of degree 5.
Degree of polynomial
Constant polynomial:
For example:f(x) = 7, g(x) = -3/2, h(x) = 2
are constant polynomials.The degree of constant polynomials is not defined.
Linear polynomial:
For example: p(x) = 4x – 3, q(x) = 3y are linear polynomials.
Any linear polynomial is in the form ax + b, where a, b are real
nos. and a ≠ 0.It may be a monomial or a binomial. F(x) = 2x – 3 is binomial
whereas
g (x) = 7x is monomial.
Types of polynomial:
A polynomial of degree two is called a quadratic polynomial. f(x) = √3x2 – 4/3x + ½, q(w) = 2/3w2 + 4 are quadratic polynomials with real coefficients.Any quadratic is always in the form f(x) = ax2 + bx +c where a,b,c are real nos. and a ≠ 0.
A polynomial of degree three is called a cubic
polynomial. f(x) = 9/5x3 – 2x2 + 7/3x
_1/5 is a cubic polynomial in variable x.
Any cubic polynomial is always in the form f(x = ax3 + bx2 +cx + d where a,b,c,d
are real nos.
Value’s & zero’s of Polynomial
A real no. x is a zero of the polynomial f(x),is f(x) =
0
Finding a zero of the polynomial means solving
polynomial equation f(x) = 0.
If f(x) is a polynomial and y is any real no. then real no. obtained by replacing x by y in f(x) is called the value of f(x) at x = y and
is denoted by f(x).
Value of f(x) at x = 1
f(x) = 2x2 – 3x – 2 f(1) = 2(1)2 – 3 x 1 – 2
= 2 – 3 – 2
= -3
Zero of the polynomial
f(x) = x2 + 7x +12 f(x) = 0
x2 + 7x + 12 = 0
(x + 4) (x + 3) = 0
x + 4 = 0 or, x + 3 = 0
x = -4 , -3
QUADRATICQUADRATIC
☻ α + β = - coefficient of x
Coefficient of x2
= - ba
☻ αβ = constant termCoefficient of x2
= ca
CUBICCUBIC
α + β + γ = -Coefficient of x2 = -bCoefficient of x3 a
αβ + βγ + γα = Coefficient of x = cCoefficient of x3 a
αβγ = - Constant term = dCoefficient of x3 a
Relationships
ON VERYFYI
NG THE
RELATIONSHIP B
ETWEEN
THE ZEROES A
ND
COEFFICIEN
TS
ON FINDING THE
VALUES OF EXPRESSIONS
INVOLVING ZEROES OF
QUADRATIC POLYNOMIAL
ON FINDING AN
UNKNOWN WHEN A
RELATION BETWEEEN
ZEROES AND COEFFICIENTS
ARE GIVEN.
OF ITS A QUADRATIC
POLYNOMIAL WHEN
THE SUM AND
PRODUCT OF ITS
ZEROES ARE GIVEN.
If f(x) and g(x) are any two polynomials with g(x) ≠ 0,then we can always find polynomials q(x), and r(x) such that :
F(x) = q(x) g(x) + r(x),F(x) = q(x) g(x) + r(x),
Where r(x) = 0 or degree r(x) < degree g(x)
ON VERYFYING THE DIVISION ALGORITHM FOR POLYNOMIALS.
ON FINDING THE QUOTIENT AND REMAINDER USING DIVISION ALGORITHM.
ON CHECKING WHETHER A GIVEN POLYNOMIAL IS A FACTOR OF THE OTHER POLYNIMIAL BY APPLYING THEDIVISION ALGORITHM
ON FINDING THE REMAINING ZEROES OF A POLYNOMIAL WHEN SOME OF ITS ZEROES ARE GIVEN.