Question

1. For each of the following regular expressions find a language (i.e., a set of strings) over A = {a,b,c} that can be represented/described by that expression. (6 points) a. bac + bc b. b*ac + bc C. b*ccca* a. 2. Find a regular expression to describe the given language: {b, ac, bac, bc, ..., b”ac, bc”, ... } (3 points)

Answer 1

1)

a)bac+bc

this regular expression accepts strings bac or bc

Language is {bac,bc}

b)b*ac+bc*

Language is {ac,,bac,bbac,,bbbac,.......,b,bc,bcc,bccc,,........}

this regular expression accepts set of strings starts with any number of b's and ends with ac or start with single 'b' and ends with any number of c's.

c)b*ccca*

Language is {ccc,bccc,ccca,bbccc,bbccca,bbcccaa,..............}

this regular expression accepts set of strings starts with any number of b's followed by three c's followed by any number of a's.

2)answer)

the language i s{b,ac,bac,bc,.....,b^n ac,bc^n,.......}

regular expression is b*ac+bc*