are the following defintions exactly the same? at least they seem to
give the same results...
# let rec cube x = x*x*x;;
val cube : int -> int = <fun>
# cube 12;;
- : int = 1728
# let cubex x = x*x*x;;
val cubex : int -> int = <fun>
# cubex 12;;
- : int = 1728
#