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Previous Year Question Paper

AI/AL/CD-401 (GS) – Introduction to Discrete Structure and Linear Algebra

November 2023AIMLSEMESTER-4
November 2023
Max Marks: 70
Duration: 3 Hours
Instructions:

Attempt any five questions.

All questions carry equal marks.

Q.1
a)Unit 1

Prove that:

i) A - (B ∩ C) = (A - B) ∪ (A - C)

ii) A × (B ∩ C) = (A × B) ∩ (A × C).

b)Unit 1

With the help of Venn-diagram, prove that (A ∪ B)' = A' ∩ B' and (A ∩ B)' = A' ∪ B'.

Q.2
a)Unit 1

Consider the set Z of integers m > 1. We say that x is congruent to y modulo m written as x ≡ y (mod m) if x - y is divisible by m. Show that this defines an equivalence relation on Z.

b)Unit 1

Let Dₘ denotes the positive divisors of m ordered by divisibility. Draw the Hasse diagrams of:

i) D₁₅

ii) D₂₄.

Q.3
a)Unit 2

Consider the set Q of rational numbers and let * be the operation on Q defined by: a * b = a + b - ab.

i) Is (Q, *) a semi-group. Is it commutative.

ii) Find the identity element for *.

iii) Do any elements in Q have inverse? What is it?

b)Unit 2

Define Ring with example. Also explain Commutative ring and ring homomorphism.

Q.4
a)Unit 2

Solve the recurrence relation aₙ = 3aₙ₋₁ - 3aₙ₋₂ + aₙ₋₃, a₀ = 0, a₃ = 3, a₅ = 10.

b)Unit 3

Show that ((p ∨ q) ∧ ¬(¬p ∧ (¬q ∨ ¬r))) ∨ (¬p ∧ ¬q) ∨ (¬p ∧ ¬r) ≡ T is a tautology by laws of algebra of propositions.

Q.5
a)Unit 3

Obtain the conjunctive normal form of:

i) p ∧ (p ⇒ q)

ii) ¬p ⇒ [r ∧ (p ⇒ q)].

b)Unit 3

Check for Euler and Hamiltonian graphs for the given graph.

Q.6
a)Unit 3

What is coloring problem? Hence define coloring of graph.

b)Unit 4

Solve the simultaneous equations using Cholesky Decomposition.

Q.7
a)Unit 5

What is null hypothesis? What is its significance in statistical variance?

b)Unit 5

An agricultural research organization wants to study the effect of four types of fertilizers on the yield of crop. Fill in the blanks in the ANOVA table and test at α = 0.5, whether the fertilizers differ significantly.

Q.8
a)Unit 5

A coin was tossed 400 times and the head turned up 216 times. Test the hypothesis that the coin is unbiased.

b)Unit 4

Find the singular value decomposition of the matrix A = [[-4, -7], [1, 4]].