4. Find the regular expression for the set of all strings over {0, 1} ending with 00 and beginning with 1.
Solution: We have the input alphabets ∑ = {a, b}.
Here, the resultant regular expression will denote, “The set of all strings over the given ∑ which must start with 1 and ends with two consecutive 0’s i.e. 00.”
To fix this problem we first write the regular expression which represents the set of all strings over the given ∑. It is
(0 + 1)*
Now, the regular expression which fulfill the requirement of given problem can be written as-
1 (0 + 1)* 00
