degree (of a polynomial)

NOVEMBER 14, 2023

Degree (of a Polynomial) in Math: Definition and Properties

Definition

In mathematics, the degree of a polynomial is the highest power of the variable in the polynomial expression. It represents the complexity or size of the polynomial. The degree helps us understand the behavior and characteristics of the polynomial function.

History

The concept of degree in polynomials dates back to ancient times. The ancient Greeks, such as Euclid and Diophantus, studied polynomial equations and recognized the importance of the degree in solving them. Over the centuries, mathematicians like Descartes, Newton, and Euler further developed the theory of polynomials and their degrees.

Grade Level

The concept of degree in polynomials is typically introduced in high school mathematics, around grades 9 or 10. It is an essential topic in algebra and serves as a foundation for more advanced mathematical concepts.

Knowledge Points and Explanation

The concept of degree in polynomials involves the following key points:

  1. Monomials: A monomial is a polynomial with only one term. The degree of a monomial is simply the exponent of the variable in that term. For example, in the monomial 3x^2, the degree is 2.

  2. Polynomials: A polynomial is an expression consisting of variables, coefficients, and exponents, combined using addition, subtraction, and multiplication. The degree of a polynomial is determined by the highest degree among its monomials. For example, in the polynomial 2x^3 + 5x^2 - 3x + 1, the degree is 3.

  3. Degree of Zero: The degree of the zero polynomial, denoted as deg(0), is undefined since it does not contain any non-zero terms.

Types of Degree

There are different types of degrees in polynomials:

  1. Constant Polynomial: A polynomial with a degree of 0 is called a constant polynomial. It has no variable terms, only a constant term. For example, the polynomial 7 is a constant polynomial of degree 0.

  2. Linear Polynomial: A polynomial with a degree of 1 is called a linear polynomial. It has one variable term raised to the power of 1. For example, the polynomial 3x - 2 is a linear polynomial of degree 1.

  3. Quadratic Polynomial: A polynomial with a degree of 2 is called a quadratic polynomial. It has one variable term raised to the power of 2. For example, the polynomial 4x^2 + 2x - 1 is a quadratic polynomial of degree 2.

  4. Cubic Polynomial: A polynomial with a degree of 3 is called a cubic polynomial. It has one variable term raised to the power of 3. For example, the polynomial x^3 - 5x^2 + 3x + 2 is a cubic polynomial of degree 3.

Properties of Degree

The degree of a polynomial exhibits several properties:

  1. Addition/Subtraction: When adding or subtracting polynomials, the degree of the resulting polynomial is the highest degree among the added/subtracted polynomials.

  2. Multiplication: When multiplying two polynomials, the degree of the resulting polynomial is the sum of the degrees of the multiplied polynomials.

  3. Division: The degree of the quotient obtained by dividing one polynomial by another is the difference between the degrees of the dividend and divisor.

Finding the Degree

To find the degree of a polynomial, follow these steps:

  1. Identify the highest power of the variable in the polynomial expression.

  2. The identified power is the degree of the polynomial.

Formula for Degree

The degree of a polynomial can be expressed using the following formula:

deg(p(x)) = n

Where deg represents the degree, p(x) is the polynomial, and n is the highest power of the variable in the polynomial.

Application of Degree Formula

To apply the degree formula, substitute the polynomial expression into the formula and determine the highest power of the variable.

For example, consider the polynomial 2x^3 + 5x^2 - 3x + 1. By substituting it into the formula, we find:

deg(2x^3 + 5x^2 - 3x + 1) = 3

Therefore, the degree of the polynomial is 3.

Symbol or Abbreviation

The symbol used to represent the degree of a polynomial is "deg".

Methods for Degree

There are various methods to determine the degree of a polynomial, including:

  1. Direct Observation: By visually inspecting the polynomial expression, identify the highest power of the variable.

  2. Coefficient Analysis: Analyze the coefficients of the polynomial to determine the highest power of the variable.

  3. Algebraic Manipulation: Perform algebraic operations on the polynomial expression to simplify it and identify the highest power of the variable.

Solved Examples

  1. Find the degree of the polynomial 4x^4 - 2x^3 + 7x^2 - 5x + 3.

    Solution: The highest power of the variable is 4, so the degree of the polynomial is 4.

  2. Determine the degree of the polynomial 2x^2 + 3x - 1.

    Solution: The highest power of the variable is 2, so the degree of the polynomial is 2.

  3. What is the degree of the polynomial 5?

    Solution: Since the polynomial is a constant, it has a degree of 0.

Practice Problems

  1. Find the degree of the polynomial 3x^5 - 2x^3 + 4x^2 - 7x + 1.

  2. Determine the degree of the polynomial 6x^4 + 2x^2 - 3.

  3. What is the degree of the polynomial 9x^2 - 8x + 7?

FAQ

Q: What is the degree of a polynomial? A: The degree of a polynomial is the highest power of the variable in the polynomial expression.

Q: How is the degree of a polynomial determined? A: The degree is determined by identifying the highest power of the variable in the polynomial expression.

Q: What is the degree of a constant polynomial? A: A constant polynomial has a degree of 0 since it does not contain any variable terms.

Q: Can the degree of a polynomial be negative? A: No, the degree of a polynomial is always a non-negative integer.

Q: What is the significance of the degree in polynomials? A: The degree helps us understand the complexity, behavior, and characteristics of the polynomial function. It provides insights into the number of solutions, end behavior, and graph shape.