kindly explain according to me ans shd be b & c

kindly explain according to me ans shd be b & c 

4Comments
Vivek Vikram Singh @vivek14
15 Feb 2015 06:31 pm

L(R1) = set of strings which start from 11.

L(R2)= Set of strings which end with 11.

Biggest mistake to consider L(R3) is set of strings which starts and ends with 11.

L(R3) is NOT set of strings which starts and end with 11, as it does not contain 11,which starts and ends with 11.

B option ) L(R1) U L(R2) will contain strings like {11,110,011} which is not in L(R3). So B is wrong.

C ) L(R1) will contain string eg 110 which is not in L(R3) AS L(R3) will contain at least fours 1's ,2 start and 2 end. So C is wrong.  

Arul @innovwelt
15 Feb 2015 04:06 pm

Itseems that none of the given options are true.

Obviously A) is wrong.

B), C) are wrong as explained by Vivek above.

D) is not true, as L1 ∩ L2 = 11, 1111, 11011, 11111...

here, 11 is a string which will not be there in L3.

 

Shimpy Goyal @shimpygoyal
15 Feb 2015 04:39 pm

 @ vivek how LR1 011 even though it is given strt wt 11 ?  & y cnt consider LR3  as strt & end wt 11 ????

Vivek Vikram Singh @vivek14
15 Feb 2015 06:33 pm

Sorry Shimpy,error.Corrected my answer.

L(R3) will contain at least four 1's.

and Yes, D is not correct too as explained by Arul above. 

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