1. Tail Recursion

2. Iterative Memory Use iterativeFact requires ~12 bytes of storage
Regardless of n

3. Iterative Memory Use recursiveFact requires ~8 bytes of storage
Per function call!!!

4. Limited Space Stack has X amount of space
Deep recursion will run out of memory:

5. Tail Recursion
Tail recursive function : One that does no work after recursive call other than return answer
Calculates on way in using extra parameter

6. Tail Call Optimization
Compiler can reuse stack frame… only allocate one chunk of memory