4. Why is it important for a grammar to be unambiguous?

5) (3pts) Write a regular expression for the following: S = {a,b} L = { all words that have two letter as or two letter bs in consecutive order }

6) (3pts) Write a grammar for the language consisting of strings that have n copies of the letter a followed by the same number of copies of the letter b where n > 0. For example strings ab, aabb, aaaabbbb, are in the language but a abb, ba, aaabb are not.