Polynomials
A polynomial is an expression with one or more terms involving variables raised to non-negative integer powers. Mastering polynomials is essential for factoring, equation-solving, and algebraic manipulation.
Fundamental Principles
Polynomial
An expression of the form aₙxⁿ + aₙ₋₁xⁿ⁻¹ + … + a₁x + a₀ where the exponents are non-negative integers and coefficients are real numbers.
Degree of a Polynomial
The highest power of the variable in the polynomial. E.g., 3x⁴ - 2x + 5 has degree 4.
Factor Theorem
A polynomial p(x) has (x - a) as a factor if and only if p(a) = 0.
Remainder Theorem
When a polynomial p(x) is divided by (x - a), the remainder is p(a).
Essential Formulation Tips
- Use the remainder theorem before doing full polynomial division.
- Check if (x ± simple integers) are factors by substituting them into p(x).
- Long division and synthetic division yield the same result — choose what's faster.
- Group terms strategically for factoring by grouping.
Shortcut Execution Techniques
- p(a) = 0 → (x - a) is a factor.
- Sum of all coefficients = p(1). If p(1) = 0, then (x-1) is a factor.
- Sum of coefficients of even terms = sum of odd terms → (x+1) is a factor.
- Degree of product = sum of degrees.
Contextual Inquiries (FAQs)
Q: What is the remainder when p(x) is divided by (x - 2)?
A: The remainder is p(2) by the Remainder Theorem.
Q: How do you verify if (x + 3) is a factor?
A: Check if p(-3) = 0. If yes, (x + 3) is a factor.
Q: What is a zero of a polynomial?
A: A value of x for which p(x) = 0. Zeros are the same as roots.
Example Breakdown: Applying the Remainder Theorem
Eliminates the need for long division in MCQs.By Remainder Theorem, remainder = p(2)
p(2) = 8 - 8 + 6 = 6
Remainder = 6
Example Breakdown: Applying the Factor Theorem
Quick check without performing full division.p(2) = 8 - 12 + 4 = 0
Since p(2) = 0, (x - 2) is a factor.
Example Breakdown: Factoring a Cubic Polynomial
Extremely common in competitive exams.Test x = 1: 1 - 6 + 11 - 6 = 0 → (x-1) is a factor.
Divide: x³ - 6x² + 11x - 6 = (x-1)(x² - 5x + 6)
Factor further: (x-1)(x-2)(x-3)
Polynomials Practice Set 1
Basic: identifying degrees, types, and simple evaluations.
Q1. What is the degree of 5x³ - 4x² + 7?
Q2. If p(x) = x² - 3x + 2, find p(3).
Q3. Which of the following is a polynomial?
Q4. Find the zero of p(x) = 2x - 8.
Q5. The degree of a constant polynomial (like p(x) = 7) is:
Q6. If p(x) = x³ + 2x - 1, what is p(0)?
Q7. What is the sum of coefficients of p(x) = 2x³ - x + 5?
Q8. How many zeros can a polynomial of degree 3 have?
Q9. Which term makes p(x) = 4x³ + kx² - 5 a polynomial of degree 3?
Q10. If p(a) = 0, then (x - a) is a ___ of p(x).