Awesome q2a theme
0 votes
Let A= (a + b)* ab (a + b)*, B= a*b* and C= (a + b)*. Then the relation between A, B and C:

A. A+B= C
B. $A^{R}+B^{R}=C$
C. $A^{R}$+B= C
D. None of these
in Theory of Computation by (341 points) | 38 views
All your questions are already there in GO.. :)
@hirak does not care abt ashok dinda type questions. He always waits for the Dale Steyn type questions........ hirak will set things on fire during exm.

ato chatle eibar forsa hoe jabo.. XD
Accha ........ forsa de villiers er moto batting korbi r ki ..... :P
sei sei… ( IITD laughs in background)
Prohibited flag incoming….XD

2 Answers

0 votes
by (1.2k points)
0 votes
Option c is the answer.

A generates strings with ab as substring and B generates strings of form a*b*.

Reversal of A be AR:

Let A = X(YX) where X = ( a + b )* and Y = ab

AR = ( X(YX))R = (YX)R XR = XR YR XR = (a+b)*R (ab)R ( a+b)*R = (a+b)*ba (a+b)*

AR = ( a+ b)*ba( a+b)*

Now do the union of AR and B u will get all the strings in ( a+b)* i.e. in C.
Because in A + B u will never get ba which is in C. So, just reverse A and u will get strings containing ba.
by (1.6k points)
All previous years questions are already available on so before posting any question search for the availability of the same. If you are unable to find please mention the source while posting.
Quick search syntax
tags tag:apple
author user:martin
title title:apple
content content:apple
exclude -tag:apple
force match +apple
views views:100
score score:10
answers answers:2
is accepted isaccepted:true
is closed isclosed:true
Welcome to GATE CSE Doubts, where you can ask questions and receive answers from other members of the community.
Top Users Jan 2020
  1. shashin

    1262 Points

  2. Deepakk Poonia (Dee)

    346 Points

  3. Vimal Patel

    343 Points

  4. Debapaul

    265 Points

  5. Satbir

    194 Points

  6. Pratyush Priyam Kuan

    158 Points

  7. tp21

    151 Points

  8. SuvasishDutta

    151 Points

  9. pranay562

    142 Points

  10. DukeThunders

    97 Points

Monthly Top User and those within 60% of his/her points will get a share of monthly revenue of GO subject to a minimum payout of Rs. 500. Current monthly budget for Top Users is Rs. 75.
3,085 questions
1,538 answers
89,827 users