Catalyst University Math: Simple Proof That Zero Factorial (0!) Equals 1

The video tutorial explains the concept of factorials, starting with basic examples like 5! and 7!. It then derives a general formula for N factorial, showing how to expand it. The tutorial simplifies factorial expressions using N-1 factorial and concludes by explaining why 0 factorial is equal to 1.

What is the factorial of 5?

• 25

• 120

• 15

• 5

How do you express the factorial of a number 'N'?

• N * (N-1) * (N-2) * ... * 1

• N + (N-1) + (N-2) + ... + 1

• N - (N-1) - (N-2) - ... - 1

• N / (N-1) / (N-2) / ... / 1

What is the value of 0 factorial?

• 10

• Undefined

• 1

• 0

Which of the following is a correct simplification of N factorial?

• N * (N-1) factorial

• N + (N-1) factorial

• N / (N-1) factorial

• N - (N-1) factorial

Why is 0 factorial defined as 1?

• Because 0 multiplied by any number is 1

• It's a mathematical convention to simplify expressions

• 0 factorial is undefined

• Because 0 added to any number is 1