Page 1 - Introduction to Polynomials
What is a Polynomial?
A polynomial is an algebraic expression consisting of variables and coefficients, involving only
addition, subtraction, multiplication, and non-negative integer exponents of variables.
Examples of Polynomials:
- x² + 5x + 6
- 2a³ - 4a² + a - 7
- 7y - 3
Examples that are NOT Polynomials:
- 1 divided by x
- Square root of x
- x raised to negative 2
Key Features:
- Degree: Highest power of the variable.
- Coefficient: Number multiplied by the variable.
- Constant Term: A term without a variable.
Important Points:
- Powers must be non-negative integers.
- Variables should not be in the denominator or under roots.
Page 2 - Types of Polynomials
Classification by Degree:
- Constant Polynomial: Degree 0 (example: 5)
- Linear Polynomial: Degree 1 (example: x + 2)
- Quadratic Polynomial: Degree 2 (example: x² + 3x + 2)
- Cubic Polynomial: Degree 3 (example: x³ - x + 1)
Classification by Number of Terms:
- Monomial: 1 term
- Binomial: 2 terms
- Trinomial: 3 terms
Examples:
- 7x³ + x² is a cubic binomial.
- 3 is a constant monomial.
Important Points:
- Degree affects the number of solutions.
- Number of terms affects factorization methods.
Page 3 - Remainder Theorem
The Remainder Theorem states that if a polynomial f(x) is divided by (x - a), the remainder is f(a).
Instead of dividing manually, substitute a into f(x) to find remainder easily.
Example 1:
Find remainder when f(x) = x³ + 2x² - 5x + 1 is divided by (x - 2).
Solution:
f(2) = (2)³ + 2(2)² - 5(2) + 1
= 8 + 8 - 10 + 1
=7
Thus, the remainder is 7.
Important Points:
- Always substitute opposite sign.
- If remainder is 0, divisor is a factor.
Page 4 - Factor Theorem
The Factor Theorem is a special case of the Remainder Theorem.
If f(a) = 0, then (x - a) is a factor of the polynomial f(x).
Example 1:
Check if (x - 1) is a factor of f(x) = x² - 3x + 2.
Solution:
Substitute x = 1:
f(1) = (1)² - 3(1) + 2 = 1 - 3 + 2 = 0
Since f(1) = 0, (x - 1) is a factor.
Important Points:
- Factor Theorem is useful for factorizing higher degree polynomials.
Page 5 - Long Division of Polynomials
When polynomials cannot be factored easily, use long division.
Steps:
- Arrange terms in descending order of powers.
- Divide first term of dividend by first term of divisor.
- Multiply and subtract.
- Repeat until remainder is zero or lower degree than divisor.
Example:
Divide f(x) = x³ - 2x² + 4x - 8 by (x - 2).
Important Points:
- Always align terms properly.
- Division stops when degree of remainder is less than divisor.
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