The tail of a language is dened as the set of all suxes of its strings. That is,

tail(L) = {y : xy L for some x }

(i). If L = {w {a, b} : w contains exactly three bs}, give a brief description of tail(L).

(ii). Show that if L is any regular language, then tail(L) is also a regular language. As with Question 3, you can assume = {a, b} if you like.

*(Hint: There could be various ways to prove this, but the argument I found involves starting with an NFA for L and altering it in a specic way.)