regular expression

Question

Consider the following regular expression (RE)

                                                 RE =  (a+b)*(a+b+ε)a

Which of the following is equivalent to the above RE?

• a)   (a* + b*)⁺ (aa + ba)
• b)   (ε + a+b*)⁺ a
• c)   (a + b)⁺ (a + b + ε)a
• d)   None of these

Comments

answer given is d) i think it should be b)  correct me if i am wrong.

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yes, option b) seems okay to me ...

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Thanks @vijaycs

Answer 1

From the given  regular expression we have  minimum string "a"

(a) option we can't have string "a".so option is false

(B) option we can derive minimum strings "a"and others string too which are in above language

In (c) option again we cannot derive the string "a"

So (b) option should be ans.