# ISRO CS 2017 – May

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Question 1 |

If A is a skew symmetric matrix, then A

^{t}diagonal matrix | |

A | |

-A | |

0 |

**Linear Algebra**

**ISRO CS 2017 - May**

**Discuss it**

Question 1 Explanation:

If A is skew symmetric matrix then A

^{T}= -AQuestion 2 |

If A and B be two arbitrary events, then

P(A ∩ B) = P(A)P(B) | |

P(A ∪ B) = P(A) + P(B) | |

P(A / B) = P(A ∩ B) + P(B) | |

P(A ∪ B) <= P(A) + P(B) |

**ISRO CS 2017 - May**

**Discuss it**

Question 2 Explanation:

Case:1 P(A ∪ B) = P(A) + P(B) - P (A ∩ B).
Case:2 For two mutually exclusive events, (A ∩ B) = 0, So P(A ∪ B) <= P(A) + P(B)
So, option (D) is correct.

Question 3 |

Using Newton-Raphson method, a root correct to 3 decimal places of the equation x

^{3}- 3x - 5 = 02.222 | |

2.275 | |

2.279 | |

None of the above |

**Numerical Methods and Calculus**

**ISRO CS 2017 - May**

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Question 4 |

What does the data dictionary identify?

Field names | |

Field formats | |

Field Types | |

All of these |

**Software Engineering**

**ISRO CS 2017 - May**

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Question 5 |

Which of the following concurrency control protocol ensures both conflict serializability and free from deadlock?

Time stamp ordering | |

2 Phase locking | |

Both (a) and (b) | |

None of the above |

**Transactions and concurrency control**

**ISRO CS 2017 - May**

**Discuss it**

Question 5 Explanation:

Both Time stamp ordering and 2 Phase locking protocol ensures conflict serializability but only Time stamp ordering protocol provides freedom from deadlock.

Question 6 |

ACID properties of a transactions are

Atomicity, consistency, isolation, database | |

Atomicity, consistency, isolation, durability | |

Atomicity, consistency, integrity, durability | |

Atomicity, consistency, integrity, database |

**Transactions and concurrency control**

**ISRO CS 2017 - May**

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Question 6 Explanation:

Every transaction holds ACID properties.
A: Atomicity: Either a transaction should be performed completely or it should rollback.
C: Consistency: Every transaction specifies some consistency constraints and these constraints should follow even after transaction occurs.
I: Isolation: Every transaction should be performed in isolation so that no other transaction can see the intermediate result of any transaction.
D: Durability: Every transaction performed should be recorded and despite all the failures these records must persist.

Question 7 |

What is the output of the following SQL query?

select count(*) from ((select Employee, Department from Overtime_allowance) as S natural join (select Department, OT_allowance from Overtime_allowance) as T);

16 | |

4 | |

8 | |

None of the above | |

none |

**SQL**

**ISRO CS 2017 - May**

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Question 7 Explanation:

(select Employee, Department from Overtime_allowance) as S
natural join (select Department, OT_allowance from Overtime_allowance) as T)

Table S Table R Employee Department Department OT_allowance Rama Mechanical Mechanical 5000 Gopi Electrical Electrical 2000 Sindhu Computer Computer 4000 Mahesh Civil Civil 1500Now when we apply a natural join on S and R, it matches the common attribute Department in both the tables and outputs the common tuples. So, 4 tuples will be given as the output. Correct option (B)

Question 8 |

Which symbol denote derived attributes in ER Model?

Double ellipse | |

Dashed ellipse | |

Squared ellipse | |

Ellipse with attribute name underlined |

**ER and Relational Models**

**ISRO CS 2017 - May**

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Question 8 Explanation:

Refer:Database Management System | ER Model
Correct option (B)

Question 9 |

The symmetric difference of sets A = {1, 2, 3, 4, 5, 6, 7, 8} and B = {1, 3, 5, 6, 7, 8, 9} is

{1, 3, 5, 6, 7, 8} | |

{2, 4, 9} | |

{2, 4} | |

{1, 2, 3, 4, 5, 6, 7, 8, 9} |

**Set Theory & Algebra**

**ISRO CS 2017 - May**

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Question 9 Explanation:

Symmetrical Difference of A and B = (A - B) ∪ (B - A)
(A - B) = {2, 8}
(B - A) = {9}
(A - B) ∪ ( B - A) = {2, 8} ∪ {9} = {2, 8, 9}

Question 10 |

The problems 3-SAT and 2-SAT are

Both NP-complete | |

Both in P | |

NP-complete and in P, respectively | |

Undecidable and NP-complete, respectively |

**NP Complete**

**ISRO CS 2017 - May**

**Discuss it**

Question 10 Explanation:

3-SAT problem is NP- complete problem whereas 2- SAT problem is P- class problem.
Refer: 2-Satisfiability (2-SAT) Problem
Option (C) is correct.

There are 79 questions to complete.