Example 4! = 1 So why does 𝑎! = 1 A Very Informal Proof Note: !
!
= 1 , and Let 𝑢 = 𝑎! By using substitution and using Quotient of Powers Property of Exponents 𝑎!
1 = ! = 𝑎 !!! = 𝑎 ! 𝑎
Therefore 𝑎! = 1 𝑜𝑟 1 = 𝑎!