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What is a Constant Polynomial?

Graph showing a horizontal line representing a constant polynomial at y=5
A constant polynomial is always the same value, represented as a horizontal line

A constant polynomial is a special type of polynomial that has no variables, just a constant number. It doesn't change as the variable changes, which is why we call it "constant" - it stays the same.

Here's what makes constant polynomials special:

  • They have no x terms (like x, x², x³)
  • They are written as f(x) = c where c is any number
  • Their graph is always a horizontal line
  • They have a degree of zero (except the zero polynomial)

Constant Polynomial Formula

f(x) = c

Where c is a constant number (like 5, -3, or 0.75)

Key Facts About Constant Polynomials

Chart showing constant, linear, and quadratic polynomials with examples
Constant polynomials compared to other polynomial types

Here are some important facts to remember about constant polynomials:

Degree

A non-zero constant polynomial has a degree of zero. For example:

f(x) = 7 → degree = 0

The zero polynomial (f(x) = 0) has an undefined degree.

Graph

The graph is always a horizontal line. For example:

f(x) = 4 → horizontal line at y=4

No matter what x-value you choose, y is always the same.

Behavior

Constant polynomials never change. They are the same for every input value:

f(0) = c
f(10) = c
f(-5) = c

Examples of Constant Polynomials

Real-world examples: fixed price, constant speed, room temperature
Constant relationships in real life

Constant polynomials are all around us! Here are some examples:

Fixed Price

The cost of an item that doesn't change:

f(x) = 2.50

No matter how many you buy, each item costs $2.50

Constant Speed

When something moves at a steady speed:

speed = 60 mph

The speed stays the same over time

Room Temperature

A well-controlled room maintains constant temperature:

f(t) = 72°F

Temperature stays the same regardless of time

Mathematical Examples

Polynomial Type Degree
f(x) = 5Constant (non-zero)0
g(x) = -3.2Constant (non-zero)0
h(x) = 0Zero PolynomialUndefined
p(x) = 2 + xLinear (not constant)1

Practice Quiz

Test your understanding of constant polynomials with this 5-question quiz:

1. Which of these is a constant polynomial?
2. What is the degree of the constant polynomial f(x) = 7?
3. What is the value of the constant polynomial g(x) = -3 when x = 10?
4. Which polynomial is the zero polynomial?
5. What does the graph of a constant polynomial look like?

Frequently Asked Questions

Here are answers to common questions about constant polynomials:

Math Trivia

Discover interesting facts about polynomials and mathematics:

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