### Home > A2C > Chapter 10 > Lesson 10.2.2 > Problem 10-79

10-79.

What do you think 0! is equal to? Homework Help ✎

Try it on your calculator to see what you get.

What does

_{8}*P*_{8}mean? What*should*_{8}*P*_{8}be equal to? Write_{8}*P*_{8}using the factorial formula. Why is it necessary for 0! to equal 1?Do you remember how to show that 2

^{0}= 1? You can use a sequence of powers of 2, but we also know that . Therefore 2 ^{0}= 1.

You can construct a similar pattern for 0!, starting withand then Continue the pattern and make an argument to justify that 0! = 1.

You should get 1.

Refer to the Math Notes box from Lesson 10.2.3 for help.