Convert given DFA to regular expression, I think it's just that 2 is dead state and thus can be eliminated.

Question

Comments

Dead state is a state from which there are no moves to the final state. But here 2 has transition which can lead to final state.

Answer 1

Clearly, 2 is not a Dead state as on the input b, it will transit to State 1 (from which Final State,3 can be reached) not to State 2 itself.

And for the second part of the question, the Regular Expression for the given DFA would be ;

(b (a)* b)* a ( (a+b) a* b (b (a)* b)* a )*.

U can follow up with the DFA to verify the Regular Expression.

Comments

can you minimize this expression?

---

As of now, No. I don't think there is way to reduce the RE as given DFA is already a minimal one and also no dead state are present.

Answer 2

firstly its not a dead state because you can reach the final state from expression 2 secondly to solve these questions its easier to just create an nfa if you understand the dfa i think the regular expression would be (a+b)*a

Comments

eraldin2003 $(a+b)^*a$ is not same as $(a+b)^*$

---

Regular expressions are incomplete they are made only to accept a language we don't have to show what is not accepted

---

Yes they both are not the same in (a+b)* epsilon can be accepted but in (a+b)*a atleast a is accepted while generating regular expression we tend to derive it based on the Nfa regular expressions are incomplete that is why dead states are not required we generate regular expression to just accept a language we are not bothered by what else can be accepted.

My conclusion - regular expressions are derivatives of nfas not dfas we can't apply he DFA logic of having to complete the machine because nfas are incomplete machines so are regular expressions