# UGC NET COMPUTER SCIENCE SOLVED PAPERS 2017-19 - UGC NET Computer Science November 2017 Paper 3

>>>>>>>>UGC NET Computer Science November 2017 Paper 3

• Option : D
• Explanation :
Recursive languages are closed under intersection. So, option (D) is correct.

• A

Concatenation  • B

Complementation  • C

Kleene Star  • D

Union  • Option : B
• Explanation :
Context free grammar are not closed under Complementation. So, option (B) is correct.

• A

Only L1 and L2 are context free languages  • B

Only L1 and L3 are context free languages  • C

Only L2 and L3 are context free languages  • D

L1, L2 and L3 are context free languages  • Option : D
• Explanation :
1. In L1 we have to check for m is not equal to n. there are infinite no which falls under this category but we have only one comparision with m and n. So it is context free language.
2. In L2 one comparison with infinite possibilities of m and n, it is alos a CFL
3. In L3 one comparison with infinite possibilities of m and n, it is alos a CFL
So, option (D) is correct.

(j2 = −1) Where values of x and y are _____, _____ respectively.

• A

1, -1  • B

-1, 1  • C

-j, j  • D

j, -j  The value of b gives the units of entropy. The unit for b=10 is :
(1) bits
(2) bann
(3) nats  (4) deca

• A

(1) and (3)  • B

(2) and (3)  • C

(1),(2)and(3)  • D

All are correct.  