NIELIT 2017 DEC Scientist B - Section B: 35

Question

Which of the following regular expression is equal to $(r_1+r_2)^*$?

• A. $r_1^*r_2^*$
• B. $(r_1r_2)^*$
• C. $r_1^*r_2^*+r_1r_2$
• D. $(r_1^*r_2^*)^*$

Answer 1

In General

(a+b)*=(a*+b)*=(a+b*)*=(a*+b*)*=(a*b*)*

ANS: Option D

Answer 2

(r₁+r₂)* = (r₁* + r₂*)* = (r₁*r₂*)*

OPTION (D)