Permutations and Factorials

Permutations and factorials are fundamental concepts in combinatorics, the branch of mathematics dealing with counting and arrangement possibilities.

Factorial of a non-negative integer n, denoted as n!, is the product of all positive integers less than or equal to n. Mathematically it is represented as:

n! = n × (n-1) × (n-2) × (n-3) × (n-4)…….. × 1

A permutation is an arrangement of a set of objects in a specific order. The concept is essential when the order of arrangement matters.

For example: Number of ways to arrange 3 objects (A, B, C) is 3! = 6 (ABC, ACB, BAC, BCA, CAB, CBA).

Zero Factorial (0!)

The value of zero factorial is 1. Factorial of any number “n” is calculated by multiplying all the numbers between n and 1 (including n). So one might ask what is the value of zero factorial, the value of 0! factorial is 1 and this is calculated using various methods.

In this article we are going to learn about the definition of factorial, how factorial is calculated, the Derivation of 0! is equal to 1, Examples and FAQs related to Factorial, and others.

Table of Content

  • Definition of Factorial
  • How is Factorial Calculated?
  • What is Factorial of 0?
  • Derivation of Zero Factorial is Equal to 1
  • Permutations and Factorials
  • Factorial of Negative Number
  • Operations On Factorial
  • Sample Problems on Zero Factorial
  • Practice Problems on Zero Factorial
  • Zero Factorial – FAQs

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Definition of Factorial

Factorial of any number is calculated by finding the product of n and all numbers less than n, till it reaches 1. Another definition of factorial can be defined as the factorial of a whole number is the function that multiplies the number by every natural number less than it. The factorial of any number is represented by denoting an exclamation mark after it, symbolically it is written as n!. Factorials are used to calculate permutation and combination....

How is Factorial Calculated?

Let us suppose we have to calculate the factorial of n, then the factorial of n is denoted by putting an exclamation mark after n i.e. n!...

What is Factorial of 0?

The value of Zero factorial is equal to 1. Symbolically, it can be represented as 0! = 1. We can prove that the value of zero factorial is equal to 1 in different ways. As factorial is used to calculate the permutation and combination of any number, logically the meaning of zero factorial is to arrange data that contains no value. So, the way of arranging any data which contains no values is in only one way. So the value of 0! is equal to 1....

Derivation of Zero Factorial is Equal to 1

The formula for calculating the factorial of any number is equal to the product of all the positive numbers less than or equal to a number....

Permutations and Factorials

Permutations and factorials are fundamental concepts in combinatorics, the branch of mathematics dealing with counting and arrangement possibilities....

Factorial of Negative Number

Factorial of a negative number is not defined/undefined. If we extend the definition of factorial using the gamma function then the factorial of a negative number is calculated, but in general, it is not defined. Let’s see how we can prove the factorial of negative numbers is undefined....

Operations On Factorial

We perform basic mathematical operations such as addition, subtraction, multiplication, and division similar to we calculate for any number using factorial. Let’s understand this with examples,...

Sample Problems on Zero Factorial

Problem 1: Find the value of the given expression: 5! + 0! + 6! + 0! + 1!...

Practice Problems on Zero Factorial

P1. Evaluate the expression: (3 + 2)!...

Zero Factorial – FAQs

What is the Value of Zero Factorial?...