Constant in Maths (original) (raw)

Last Updated : 14 Apr, 2026

A constant is a value that does not change. It is fixed and remains the same throughout a given problem or equation. Constants can appear in various forms, such as specific numbers, variables with known values, or symbols representing unchanging values.

**Example: In the expression: 5+x, 5 is a constant (its value does not change) and x is a variable (its value can change).

Some more examples for constants are:

• **Pi (π): The ratio of the circumference of a circle to its diameter, approximately 3.14159, is a constant because it has the same value for any circle.
• **Euler’s Number (e): A mathematical constant approximately equal to 2.71828, used in exponential growth and logarithmic functions.
• **Speed of Light (c): In physics, the speed of light is constant at approximately 299,792,458 meters per second.

Constant Term in Algebraic Expression

In an algebraic expression, a constant term is a term that does not contain any variables and has a fixed value. It is simply a number that stands alone in the expression.

For example, in algebraic expression 2x2 + 3x - 11, (**-11) is constant.

Types of Constant

In mathematics, constants are values that do not change and remain fixed throughout mathematical operations or equations. They can be classified into several types based on their properties:

• **Fixed Constants: These are constants with specific, unchanging values that remain constant across all calculations.

Examples include mathematical constants like π (pi) or Euler's number(e).

• **Mathematical Constants****:** These constants arise from mathematical principles and have significant mathematical importance. They often appear in formulas, equations, and mathematical identities.

Examples include Euler's number (e), the golden ratio (φ), and the imaginary unit (i).

• **Physical Constants****:** Physical constants are values that represent fundamental physical quantities and are used in scientific calculations and equations.

Examples include the speed of light in vacuum (c), the gravitational constant (G), and the Planck constant (h).

• **Universal Constants: Universal constants are values that are consistent across different mathematical and scientific disciplines. They are widely used in various mathematical and scientific contexts.

Examples include the speed of light (c) and Planck's constant (h).

• **Variable Constants: Variable constants are values that remain constant within a specific mathematical context or equation but may vary in different contexts or equations. They are often represented by symbols and can change value depending on the situation.

Examples include constants used in algebraic equations, such as a, b, and c in a quadratic equation.

**Also Check

• Difference between constant and variables
• Constant Function

Solved Examples

**Example 1: Identify the constant term in the given algebraic expression: 3x2 + 2xy − 7.

**Solution:

Given Expression, 3x2 + 2xy − 7

Constant term in the expression is −7

**Example 2: Compute the value of the given algebraic expression: 5a + 3 when a = 2.

**Solution:

Given Expression, 5a + 3 when a = 2

Substituting a = 2 into the expression,
= 5(2) + 3
= 10 + 3 = 13

**Example 3: Solve the equation 2x + 8 = 16 for the value of x.

**Solution:

Given Expression,

2x + 8 = 16
⇒ 2x = 16 -8
⇒ 2x = 8
⇒ x = 8/2
⇒ x = 4