EASY
9th Telangana Board
IMPORTANT
Earn 100

Write whether the following statement is 'True' or 'False'. Justify your answer.

Degree of zero polynomial is zero.

Important Points to Remember in Chapter -1 - Polynomials and Factorisation from Telangana Board Mathematics Class 9 Solutions

1. Some useful Identities:

(i) a+b2=a2+b2+2ab

(ii) a-b2=a2+b2-2ab

(iii) a+ba-b=a2-b2

(iv) a+b+c2=a2+b2+c2+2ab+2bc+2ca

(v) a+b3=a3+b3+3aba+b

(vi) a-b3=a3-b3-3aba-b

(vii) a3+b3=a+ba2-ab+b2

(viii) a3-b3=a-ba2+ab+b2

(ix) a3+b3+c3-3abc=a+b+ca2+b2+c2-ab-bc-ca

(x) a3+b3+c3-3abc=12a+b+ca-b2+b-c2+c-a2

(xi) If a+b+c=0 then a3+b3+c3=3abc

2. The general form of a Polynomial:

An algebraic expression of the form fx=anxn+an-1xn-1++a1x+a0 where  a0, a1, a2, , an are constants, is known as a polynomial in variable x.

3. Terms of a Polynomial:

In the polynomial fx=anxn+an-1xn-1++a1x+a0 each of anxn, an-1xn-1, , a1x, a0 is called its term and anxn, an0 called the leading term. a0 is known as the constant term.

4. Degree of a Polynomial:

A polynomial fx=anxn+an-1xn-1++a1x+a0 is of degree n, if an05. .

5. Classification of Polynomials based on Degree:

(i) A polynomial of degree 1 is called a linear polynomial. For example, fx=ax+b, a0 is a linear polynomial.

(ii) A polynomial of degree 2 is called a quadratic polynomial. Thus, fx=ax2+bx+c, a 0; is the general form of a quadratic polynomial.

(iii) A polynomial of degree 3 is called a cubic polynomial. Thus, fx=ax3+bx2+cx+d, a 0; is the general form of a cubic polynomial.

6. Zeros of a Polynomial:

(i) A real number α is a zero (or root) of a polynomial f(x), if f(α)=0.

(ii) A polynomial of degree n has maximum of n roots.

(iii) A linear polynomial f(x)=ax+b, a0 has a unique root given by x=-ba

(iv) A non-zero constant polynomial has no root.

(v) Every real number is a root of the zero polynomial.

(vi) If f(x) is a polynomial with integral coefficients and the leading coefficient is 1, then any integer root of f(x) is a factor of the constant term.

(vii) Let fx=anxn+an-1xn-1++a1x+an, an0 be a polynomial. Then, bc (a rational fraction in lowest terms) is a root of f(x), if b is a factor of constant term a0 and c is a factor of the leading term an.

7. Remainder Theorem:

Let f(x) be a polynomial of degree greater than or equal to one and a be any real number. If f(x) is divisible by (x-a), then the remainder is equal to f(a).

8. Factor Theorem:

Let f(x) be a polynomial of degree greater than or equal to one and a be real number such that f(a)=0, then (x-a) is a factor of f(x). Conversely, if (x-a) is a factor of f(x), then f(a)=0.