2024 100404

B. Tech 4th Semester Examination, 2024

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct option/answer the following (Any seven question only):

Q1.1

The function $ f:R \rightarrow R $ defined by $ f(x)=x^3+5 $

a)

One-One but not onto

b)

Onto but not One-One

c)

Both One-One and Onto

d)

None of these

Q1.2

Consider the following relation R on a set $ A=\{1,2,3,4\} $: R = {(1,1), (1, 3), (3, 2), (2, 2), (3, 3), (3, 1), (2, 3), (1, 4), (4, 4)} Then

a)

Reflexive

b)

Symmetric

c)

Transitive

d)

Equivalence

Q1.3

Out of the following which of these integers is not prime?

a)

23

b)

59

c)

21

d)

71

Q1.4

The Greatest common divisor of 0 and 11

a)

0

b)

1

c)

11

d)

Does not exist

Q1.5

Suppose G is a group with a binary operation * defined by $ a*b=a+b+1 $, for $ a, b \in G $ then

a)

Identity element = -1

b)

Identity element = 1

c)

Identity element = -2

d)

Identity element = 2

Q1.6

The field which contains at least _____ element/elements

a)

0

b)

1

c)

2

d)

3

Q1.7

The set of integers with respect to addition is

a)

Abelian group

b)

Cyclic group

c)

Both (i) and (ii)

d)

None of these

Q1.8

The total number of edges in a complete graph of n vertices is

a)

nn

b)

n2\frac{n}{2}

c)

n21n^2-1

d)

n(n1)2\frac{n(n-1)}{2}

Q1.9

In any undirected graph, the sum of degrees of all vertices

a)

must be even

b)

is a twice the number of edges

c)

must be odd

d)

Both (i) and (ii)

Q1.10

$ (p \rightarrow q) \wedge (r \rightarrow q) $ is equivalent to

a)

(pr)q(p \vee r) \rightarrow q

b)

p(rp)p \vee (r \rightarrow p)

c)

p(rq)p \vee (r \rightarrow q)

d)

p(qr)p \rightarrow (q \rightarrow r)

Q.2 Solve both questions :

Q2.1

Given $ A=\{1,2,3\} $, $ B=\{7,8\} $ and $ R=\{(1,7), (2, 7), (1, 8), (3, 8)\} $, find $ R^{-1} $ (inverse of R) and $ R' $ complement of R.

Q2.2

Consider $ A=B=C=R $ set of real numbers and let $ f:A \rightarrow B $, $ g: B \rightarrow C $ defined by $ f(x)=x+9 $ and $ g(y)=y^2+3 $ find the following composition functions: $ (f \circ g)(a) $, $ (g \circ f)(a) $, $ (g \circ f)(x) $, $ (f \circ g)(-3) $.

Q.3 Solve both questions :

Q3.1

What is the negation of each of the following propositions? (i) Today is Tuesday (ii) A cow is an animal (iii) No one wants to buy my house

Q3.2

Determine the truth value of each of the following statements (i) $ 4+3=7 $ and $ 6+2=8 $ (ii) $ 2+3=4 $ and $ 3+1=2 $

Q.4 Solve both questions :

Q4.1

Show that the set of rational numbers Q forms an abelian group.

Q4.2

Define a ring, give an example of a commutative ring without zero divisors and a non-commutative ring with identity.

Q.5 Solve both questions :

Q5.1

Describe the Fundamental Theorem of Arithmetic. Factorize the number '324' and represent it as a product of primes.

Q5.2

Use the Euclidean algorithm to find the greatest common divisor of each pair of integers, (i) 60, 90 (ii) 414, 662

Q.6 Solve both questions :

Q6.1

Describe a graph model that can be used to represent all forms of electronic communication between two people in a single graph. What kind of graph is needed?

Q6.2

Explain the complete graph and prove that $ k_5 $ (complete graph) is a nonplanar graph.

Q.7 Solve both questions :

Q7.1

Explain the congruence relation. Let $ n $ be a positive integer then: (i) If $ a \equiv b \pmod{n} $, then $ b \equiv a \pmod{n} $ (ii) If $ a \equiv b \pmod{n} $ and $ b \equiv c \pmod{n} $, then $ a \equiv c \pmod{n} $.

Q7.2

Show that $ p \Leftrightarrow q \equiv (p \Rightarrow q) \wedge (q \Rightarrow p) $

Q.8 Solve both questions :

Q8.1

Write short notes of the following: (i) Eulerian Graph (ii) Graph Coloring

Q8.2

Write short notes of the following: (i) Chromatic number (ii) Perfect Graph

Q.9 Solve both questions :

Q9.1

What is the field? Show that $ (Q, +, \times) $ is a field.

Q9.2

If in a ring R with $ (xy)^2=x^2y^2 $ for all $ x, y \in R $, then R is commutative.


2024 V5 100404

B. Tech 4th Semester Examination, 2024

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct option/answer the following (Any seven question only):

Q1.1

The function $ f:R \rightarrow R $ defined by $ f(x)=x^3+5 $

a)

One-One but not onto

b)

Onto but not One-One

c)

Both One-One and Onto

d)

None of these

Q1.2

Consider the following relation R on a set $ A=\{1,2,3,4\} $: R = {(1,1), (1, 3), (3, 2), (2, 2), (3, 3), (3, 1), (2, 3), (1, 4), (4, 4)} Then

a)

Reflexive

b)

Symmetric

c)

Transitive

d)

Equivalence

Q1.3

Out of the following which of these integers is not prime?

a)

23

b)

59

c)

21

d)

71

Q1.4

The Greatest common divisor of 0 and 11

a)

0

b)

1

c)

11

d)

Does not exist

Q1.5

Suppose G is a group with a binary operation * defined by $ a*b=a+b+1 $, for $ a, b \in G $ then

a)

Identity element = -1

b)

Identity element = 1

c)

Identity element = -2

d)

Identity element = 2

Q1.6

The field which contains at least _____ element/elements

a)

0

b)

1

c)

2

d)

3

Q1.7

The set of integers with respect to addition is

a)

Abelian group

b)

Cyclic group

c)

Both (i) and (ii)

d)

None of these

Q1.8

The total number of edges in a complete graph of n vertices is

a)

nn

b)

n2\frac{n}{2}

c)

n21n^2-1

d)

n(n1)2\frac{n(n-1)}{2}

Q1.9

In any undirected graph, the sum of degrees of all vertices

a)

must be even

b)

is a twice the number of edges

c)

must be odd

d)

Both (i) and (ii)

Q1.10

$ (p \rightarrow q) \wedge (r \rightarrow q) $ is equivalent to

a)

(pr)q(p \vee r) \rightarrow q

b)

p(rp)p \vee (r \rightarrow p)

c)

p(rq)p \vee (r \rightarrow q)

d)

p(qr)p \rightarrow (q \rightarrow r)

Q.2 Solve both questions :

Q2.1

Given $ A=\{1,2,3\} $, $ B=\{7,8\} $ and $ R=\{(1,7), (2, 7), (1, 8), (3, 8)\} $, find $ R^{-1} $ (inverse of R) and $ R' $ complement of R.

Q2.2

Consider $ A=B=C=R $ set of real numbers and let $ f:A \rightarrow B $, $ g: B \rightarrow C $ defined by $ f(x)=x+9 $ and $ g(y)=y^2+3 $ find the following composition functions: $ (f \circ g)(a) $, $ (g \circ f)(a) $, $ (g \circ f)(x) $, $ (f \circ g)(-3) $.

Q.3 Solve both questions :

Q3.1

What is the negation of each of the following propositions? (i) Today is Tuesday (ii) A cow is an animal (iii) No one wants to buy my house

Q3.2

Determine the truth value of each of the following statements (i) $ 4+3=7 $ and $ 6+2=8 $ (ii) $ 2+3=4 $ and $ 3+1=2 $

Q.4 Solve both questions :

Q4.1

Show that the set of rational numbers Q forms an abelian group.

Q4.2

Define a ring, give an example of a commutative ring without zero divisors and a non-commutative ring with identity.

Q.5 Solve both questions :

Q5.1

Describe the Fundamental Theorem of Arithmetic. Factorize the number '324' and represent it as a product of primes.

Q5.2

Use the Euclidean algorithm to find the greatest common divisor of each pair of integers, (i) 60, 90 (ii) 414, 662

Q.6 Solve both questions :

Q6.1

Describe a graph model that can be used to represent all forms of electronic communication between two people in a single graph. What kind of graph is needed?

Q6.2

Explain the complete graph and prove that $ k_5 $ (complete graph) is a nonplanar graph.

Q.7 Solve both questions :

Q7.1

Explain the congruence relation. Let $ n $ be a positive integer then: (i) If $ a \equiv b \pmod{n} $, then $ b \equiv a \pmod{n} $ (ii) If $ a \equiv b \pmod{n} $ and $ b \equiv c \pmod{n} $, then $ a \equiv c \pmod{n} $.

Q7.2

Show that $ p \Leftrightarrow q \equiv (p \Rightarrow q) \wedge (q \Rightarrow p) $

Q.8 Solve both questions :

Q8.1

Write short notes of the following: (i) Eulerian Graph (ii) Graph Coloring

Q8.2

Write short notes of the following: (i) Chromatic number (ii) Perfect Graph

Q.9 Solve both questions :

Q9.1

What is the field? Show that $ (Q, +, \times) $ is a field.

Q9.2

If in a ring R with $ (xy)^2=x^2y^2 $ for all $ x, y \in R $, then R is commutative.


2023 100404

End Semester Examination - 2023

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Write the answer of the following (Any seven question only):

Q1.1

Let A be the set odd positive integers less than 10. Then cardinality of A, |A| is

a)

5

b)

9

c)

6

d)

4

Q1.2

If m is the number of objects (pigeons) and n is the number of boxes (pigeonholes), then the function is both one-to-one and onto if

a)

m < n

b)

m=nm = n

c)

m > n

d)

none of these

Q1.3

If $ A \times B = B \times A $, (Where A and B are general matrices) then

a)

A=ϕA = \phi

b)

A=BA = B'

c)

B=AB = A

d)

A=BA' = B

Q1.4

A partial ordered relation is transitive, reflexive and

a)

Anti symmetric

b)

bi symmetric

c)

anti reflexive

d)

asymmetric

Q1.5

If B is a Boolean Algebra, then which of the following is true

a)

B is a finite but complemented lattice

b)

B is a finite, complemented and distributive lattice

c)

B is a finite, Distributive but not complemented lattice

d)

B is not distributive lattice

Q1.6

$ P \rightarrow q $ is logically equivalent to

a)

qp-q \rightarrow p

b)

Pq-P \rightarrow q

c)

Pq-P \wedge q

d)

pq-p \vee q

Q1.7

If $ f(x) = \cos x $ and $ g(x) = x^3 $ then $ (f \circ g)(x) $ is

a)

(cosx)3(\cos x)^3

b)

cos3x\cos 3x

c)

x(cosx)3x^{(\cos x)^3}

d)

cos(x3)\cos(x^3)

Q1.8

The number of distinguishable permutations of the letters in the word BANANA are

a)

60

b)

36

c)

20

d)

10

Q1.9

Which of the following pair is not congruent modulo 7?

a)

10, 24

b)

25, 56

c)

-31, -15

d)

-64, -15

Q1.10

Let $ N=\{1,2,3,........\} $ be ordered by divisibility, which of the following subset is totally ordered

a)

(2, 6, 24)

b)

(3, 5, 15)

c)

(2, 9, 16)

d)

(4, 15, 30)

Q.2 Solve both questions :

Q2.1

Let $ A = B = \{x | -1 \le x \le 1\} $ for each of the following functions state where it is injective, surjective or bijective: i) $ g(x) = \sin \pi x $ ii) $ b(x) = \frac{2x}{3} $

Q2.2

Let $ f(x) = x+2 $, $ g(x) = x-2 $, $ h(x) = 3x $ find (i) $ f \circ g $ (ii) $ f \circ g \circ h $

Q.3 Solve both questions :

Q3.1

Find the power set of each of these sets: i) $ \{a,b\} $ ii) $ \{\phi, \{\phi\}\} $

Q3.2

Use Cantor's diagonal argument to prove that set F of all functions $ f: (0,1) \rightarrow R $ has larger Cardinality than |R|.

Q.4 Solve this question :

Q4.1

Determine if the sets are countable or uncountable: a.) the set A of all function $ g: Z_{+} \rightarrow Z_{+} $ b.) The set B of all functions $ f: Z_{+} \rightarrow \{0,1\} $

Q.5 Solve this question :

Q5.1

Prove the following by using the principle of mathematical induction for all $ n \in N $: $ 1^3 + 2^3 + 3^3 + \dots + n^3 = \left(\frac{n(n+1)}{2}\right)^2 $

Q.6 Solve this question :

Q6.1

State and prove Division algorithm theorem well-ordering principle.

Q.7 Solve both questions :

Q7.1

Check the validity of the following argument all integers are rational numbers. Some integers are powers of 5. Therefore, some rational numbers are powers of 5.

Q7.2

A grocery store employee is stocking apples. Each apple is a different color. There are 10 apples left in the box and the employee pulls out 2 of them at random. What is the probability that the employee pulls out one pink apple and yellow apple?

Q.8 Solve this question :

Q8.1

Let $ \Psi: G \rightarrow H $ be a homomorphism of groups. Show that if $ a \in G $ has order n, then $ \Psi(a) \in H $ has order dividing n.

Q.9 Solve both questions :

Q9.1

Consider the given graph. (a) Does a Hamiltonian path exist? If so describe it. If not say why not.

(b) Does an Eulerian path exist? If so describe it. If not say why not.

Question Diagram

2023 V4 100404

End Semester Examination - 2023

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Write the answer of the following (Any seven question only):

Q1.1

Let A be the set odd positive integers less than 10. Then cardinality of A, |A| is

a)

5

b)

9

c)

6

d)

4

Q1.2

If m is the number of objects (pigeons) and n is the number of boxes (pigeonholes), then the function is both one-to-one and onto if

a)

m < n

b)

m=nm = n

c)

m > n

d)

none of these

Q1.3

If $ A \times B = B \times A $, (Where A and B are general matrices) then

a)

A=ϕA = \phi

b)

A=BA = B'

c)

B=AB = A

d)

A=BA' = B

Q1.4

A partial ordered relation is transitive, reflexive and

a)

Anti symmetric

b)

bi symmetric

c)

anti reflexive

d)

asymmetric

Q1.5

If B is a Boolean Algebra, then which of the following is true

a)

B is a finite but complemented lattice

b)

B is a finite, complemented and distributive lattice

c)

B is a finite, Distributive but not complemented lattice

d)

B is not distributive lattice

Q1.6

$ P \rightarrow q $ is logically equivalent to

a)

qp-q \rightarrow p

b)

Pq-P \rightarrow q

c)

Pq-P \wedge q

d)

pq-p \vee q

Q1.7

If $ f(x) = \cos x $ and $ g(x) = x^3 $ then $ (f \circ g)(x) $ is

a)

(cosx)3(\cos x)^3

b)

cos3x\cos 3x

c)

x(cosx)3x^{(\cos x)^3}

d)

cos(x3)\cos(x^3)

Q1.8

The number of distinguishable permutations of the letters in the word BANANA are

a)

60

b)

36

c)

20

d)

10

Q1.9

Which of the following pair is not congruent modulo 7?

a)

10, 24

b)

25, 56

c)

-31, -15

d)

-64, -15

Q1.10

Let $ N=\{1,2,3,........\} $ be ordered by divisibility, which of the following subset is totally ordered

a)

(2, 6, 24)

b)

(3, 5, 15)

c)

(2, 9, 16)

d)

(4, 15, 30)

Q.2 Solve both questions :

Q2.1

Let $ A = B = \{x | -1 \le x \le 1\} $ for each of the following functions state where it is injective, surjective or bijective: i) $ g(x) = \sin \pi x $ ii) $ b(x) = \frac{2x}{3} $

Q2.2

Let $ f(x) = x+2 $, $ g(x) = x-2 $, $ h(x) = 3x $ find (i) $ f \circ g $ (ii) $ f \circ g \circ h $

Q.3 Solve both questions :

Q3.1

Find the power set of each of these sets: i) $ \{a,b\} $ ii) $ \{\phi, \{\phi\}\} $

Q3.2

Use Cantor's diagonal argument to prove that set F of all functions $ f: (0,1) \rightarrow R $ has larger Cardinality than |R|.

Q.4 Solve this question :

Q4.1

Determine if the sets are countable or uncountable: a.) the set A of all function $ g: Z_{+} \rightarrow Z_{+} $ b.) The set B of all functions $ f: Z_{+} \rightarrow \{0,1\} $

Q.5 Solve this question :

Q5.1

Prove the following by using the principle of mathematical induction for all $ n \in N $: $ 1^3 + 2^3 + 3^3 + \dots + n^3 = \left(\frac{n(n+1)}{2}\right)^2 $

Q.6 Solve this question :

Q6.1

State and prove Division algorithm theorem well-ordering principle.

Q.7 Solve both questions :

Q7.1

Check the validity of the following argument all integers are rational numbers. Some integers are powers of 5. Therefore, some rational numbers are powers of 5.

Q7.2

A grocery store employee is stocking apples. Each apple is a different color. There are 10 apples left in the box and the employee pulls out 2 of them at random. What is the probability that the employee pulls out one pink apple and yellow apple?

Q.8 Solve this question :

Q8.1

Let $ \Psi: G \rightarrow H $ be a homomorphism of groups. Show that if $ a \in G $ has order n, then $ \Psi(a) \in H $ has order dividing n.

Q.9 Solve both questions :

Q9.1

Consider the given graph. (a) Does a Hamiltonian path exist? If so describe it. If not say why not.

(b) Does an Eulerian path exist? If so describe it. If not say why not.

Question Diagram

2022 100404

B.Tech 4th Semester Exam., 2022 (New Course)

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer of the following (any seven):

Q1.1

The statement $ (\sim P \leftrightarrow Q) \wedge \sim Q $ is true, when

a)

P: True, Q: False

b)

P: True, Q: True

c)

P: False, Q: True

d)

P: False, Q: False

Q1.2

Which of the following statements regarding sets is false?

a)

AA=AA \cap A = A

b)

AA=AA \cup A = A

c)

A(BC)=(AB)(AC)A - (B \cap C) = (A - B) \cup (A - C)

d)

(AB)=AB(A \cup B)' = A' \cup B'

Q1.3

What is the induction hypothesis assumption for the inequality $ m! > 2^m $ where $ m \ge 4 $?

a)

For m=km = k, (k+1)! > 2^k holds

b)

For m=km = k, k! > 2^k holds

c)

For m=km = k, k! > 3^k holds

d)

For m=km = k, k! > 2^{k+1} holds

Q1.4

A simple graph can have

a)

multiple edges

b)

self-loops

c)

parallel edges

d)

no multiple edges, self-loops and parallel edges

Q1.5

An undirected graph has 8 vertices labelled 1, 2, ..., 8 and 31 edges. Vertices 1, 3, 5, 7 have degree 8 and vertices 2, 4, 6, 8 have degree 7. What is the degree of vertex 8?

a)

15

b)

8

c)

5

d)

23

Q1.6

A graph which has the same number of edges as its complement must have number of vertices congruent to ___ or ___ modulo 4 (for integral values of number of edges).

a)

6k,6k16k, 6k-1

b)

4k,4k+14k, 4k+1

c)

k,k+2k, k+2

d)

2k+1,k2k+1, k

Q1.7

A graph which consists of disjoint union of trees is called

a)

bipartite graph

b)

forest

c)

caterpillar tree

d)

labelled tree

Q1.8

Which of the following two sets are equal?

a)

A={1,2}A = \{1, 2\} and B={1}B = \{1\}

b)

A={1,2}A = \{1, 2\} and B={1,2,3}B = \{1, 2, 3\}

c)

A={1,2,3}A = \{1, 2, 3\} and B={2,1,3}B = \{2, 1, 3\}

d)

A={1,2,4}A = \{1, 2, 4\} and B={1,2,3}B = \{1, 2, 3\}

Q1.9

If $ C_n $ is the nth cyclic graph, where $ n > 3 $ and n is odd, determine the value of $ X(C_n) $

a)

32572

b)

16631

c)

3

d)

310

Q1.10

The number of edges in a regular graph of degree 46 and 8 vertices is

a)

347

b)

230

c)

184

d)

186

Q.2 Solve both questions :

Q2.1

Let $ D = \{-48, -14, -8, 0, 1, 3, 16, 23, 26, 32, 36\} $. Determine which of the following statements are true and which are false. Provide counterexamples for those statements that are false.
(i) $ \forall x \in D $, if x is odd, then $ x > 0 $
(ii) $ \forall x \in D $, if x is less than 0, then x is even
(iii) $ \forall x \in D $, if x is even, then $ x \le 0 $

Q2.2

Indicate which of the following statements are true and which are false. Justify your answers as best you can:
(i) $ \forall x \in Z^+ $, $ \exists y \in Z^+ $ such that $ x = y + 1 $
(ii) $ \forall x \in Z $, $ \exists y \in Z $ such that $ x = y + 1 $
(iii) $ \exists x \in R $ such that $ \forall y \in R $, $ x = y + 1 $
(iv) $ \forall x \in R^+ $, $ \exists y \in R^+ $ such that $ xy = 1 $
(v) $ \forall x \in R $, $ \exists y \in R $ such that $ xy = 1 $
(vi) $ \forall x \in Z^+ $ and $ \forall y \in Z^+ $ $ \exists z \in Z^+ $ such that $ z = x - y $
(vii) $ \forall x \in Z $ and $ \forall y \in Z $, $ \exists z \in Z $ such that $ z = x - y $
(viii) $ \exists u \in R^+ $ such that $ \forall v \in R^+ $, $ uv < v $

Q.3 Solve both questions :

Q3.1

Prove the following:
(i) There is a real number x such that $ x > 1 $ and $ 2^x > x^{10} $.
(ii) There is an integer n such that $ 2n^2 - 5n + 2 $ is prime.

Q3.2

Disprove that for all real numbers a and b, if $ a < b $, then $ a^2 < b^2 $.

Q.4 Solve all three questions :

Q4.1

Show that $ p \vee (q \wedge r) $ and $ (p \vee q) \wedge (p \vee r) $ are logically equivalent. This is the distributive law of disjunction over conjunction.

Q4.2

Find the greatest common divisor of 414 and 662 using the Euclidean algorithm.

Q4.3

If a and b are positive integers, then prove that there exists integers s and t such that $ gcd(a,b) = sa + tb $.

Q.5 Solve both questions :

Q5.1

Use mathematical induction to prove this formula for the sum of a finite number of terms of a geometric progression with initial term a and common ratio r:
$ \sum_{j=0}^{n} ar^j = a + ar + ar^2 + \cdots + ar^n = \frac{ar^{n+1}-a}{r-1} $ when $ r \ne 1 $, where n is a non-negative integer.

Q5.2

Write short notes on the following:
(i) Forward proof
(ii) Disjunctive and conjunctive normal form
(iii) Fundamental theorem of arithmetic

Q.6 Solve both questions :

Q6.1

An odd number of people stand in a yard at mutually distinct distances. At the same time each person throws a pie at their nearest neighbour, hitting this person. Use mathematical induction to show that there is at least one survivor, that is, at least one person who is not hit by a pie.

Q6.2

Prove Bernoulli's inequality that if $ h > -1 $, then $ 1 + nh \le (1 + h)^n $ for all non-negative integers n.

Q.7 What is pigeonhole principle? Using it, prove the following:

Q7.1

What is pigeonhole principle? Using it, prove the following:
During a month with 30 days, a baseball team plays at least one game a day, but no more than 45 games. Show that there must be a period of some number of consecutive days during which the team must play exactly 14 games.

Q7.2

What is pigeonhole principle? Using it, prove the following:
The sequence 8, 11, 9, 1, 4, 6, 12, 10, 5, 7 contains 10 terms. Note that $ 10 = 3^2 + 1 $. There are four strictly increasing subsequences of length four, namely, 1, 4, 6, 12; 1, 4, 6, 7; 1, 4, 6, 10; and 1, 4, 5, 7. There is also a strictly decreasing subsequence of length four, namely, 11, 9, 6, 5.

Q.8 Solve all questions :

Q8.1

In a Round-Robin tournament, the Tigers beat the Blue Jays, the Tigers beat the Cardinals, the Tigers beat the Orioles, the Blue Jays beat the Cardinals, the Blue Jays beat the Orioles and the Cardinals beat the Orioles. Model this outcome with a directed graph.

Q8.2

Let $ G=(V,E) $ be a simple graph. Let R be the relation on V consisting of pairs of vertices (u, v) such that there is a path from u to v or such that $ u = v $. Show that R is an equivalence relation.

Q8.3

Determine whether the following given pair of directed graphs, shown in Fig. 1 and Fig. 2, are isomorphic or not. Exhibit an isomorphism or provide a rigorous argument that none exists.

Question Diagram

Q.9 Solve all questions :

Q9.1

Use pseudocode to describe an algorithm for determining the value of a game tree when both players follow a minmax strategy.

Q9.2

Suppose that $ T_1 $ and $ T_2 $ are spanning trees of a simple graph G. Moreover, suppose that $ e_1 $ is an edge in $ T_1 $ that is not in $ T_2 $. Show that there is an edge $ e_2 $ in $ T_2 $ that is not in $ T_1 $ such that $ T_1 $ remains a spanning tree if $ e_1 $ is removed from it and $ e_2 $ is added to it, and $ T_2 $ remains a spanning tree if $ e_2 $ is removed from it and $ e_1 $ is added to it.

Q9.3

Show that a degree-constrained spanning tree of a simple graph in which each vertex has degree not exceeding 2 consists of a single Hamiltonian path in the graph.


2022 V4 100404

B.Tech 4th Semester Exam., 2022 (New Course)

Time 03 Hours
Full Marks 70
Instructions:
  • The marks are indicated in the right-hand margin.
  • There are NINE questions in this paper.
  • Attempt FIVE questions in all.
  • Question No. 1 is compulsory.

Q.1 Choose the correct answer of the following (any seven):

Q1.1

The statement $ (\sim P \leftrightarrow Q) \wedge \sim Q $ is true, when

a)

P: True, Q: False

b)

P: True, Q: True

c)

P: False, Q: True

d)

P: False, Q: False

Q1.2

Which of the following statements regarding sets is false?

a)

AA=AA \cap A = A

b)

AA=AA \cup A = A

c)

A(BC)=(AB)(AC)A - (B \cap C) = (A - B) \cup (A - C)

d)

(AB)=AB(A \cup B)' = A' \cup B'

Q1.3

What is the induction hypothesis assumption for the inequality $ m! > 2^m $ where $ m \ge 4 $?

a)

For m=km = k, (k+1)! &gt; 2^k holds

b)

For m=km = k, k! &gt; 2^k holds

c)

For m=km = k, k! &gt; 3^k holds

d)

For m=km = k, k! &gt; 2^{k+1} holds

Q1.4

A simple graph can have

a)

multiple edges

b)

self-loops

c)

parallel edges

d)

no multiple edges, self-loops and parallel edges

Q1.5

An undirected graph has 8 vertices labelled 1, 2, ..., 8 and 31 edges. Vertices 1, 3, 5, 7 have degree 8 and vertices 2, 4, 6, 8 have degree 7. What is the degree of vertex 8?

a)

15

b)

8

c)

5

d)

23

Q1.6

A graph which has the same number of edges as its complement must have number of vertices congruent to ___ or ___ modulo 4 (for integral values of number of edges).

a)

6k,6k16k, 6k-1

b)

4k,4k+14k, 4k+1

c)

k,k+2k, k+2

d)

2k+1,k2k+1, k

Q1.7

A graph which consists of disjoint union of trees is called

a)

bipartite graph

b)

forest

c)

caterpillar tree

d)

labelled tree

Q1.8

Which of the following two sets are equal?

a)

A={1,2}A = \{1, 2\} and B={1}B = \{1\}

b)

A={1,2}A = \{1, 2\} and B={1,2,3}B = \{1, 2, 3\}

c)

A={1,2,3}A = \{1, 2, 3\} and B={2,1,3}B = \{2, 1, 3\}

d)

A={1,2,4}A = \{1, 2, 4\} and B={1,2,3}B = \{1, 2, 3\}

Q1.9

If $ C_n $ is the nth cyclic graph, where $ n > 3 $ and n is odd, determine the value of $ X(C_n) $

a)

32572

b)

16631

c)

3

d)

310

Q1.10

The number of edges in a regular graph of degree 46 and 8 vertices is

a)

347

b)

230

c)

184

d)

186

Q.2 Solve both questions :

Q2.1

Let $ D = \{-48, -14, -8, 0, 1, 3, 16, 23, 26, 32, 36\} $. Determine which of the following statements are true and which are false. Provide counterexamples for those statements that are false.
(i) $ \forall x \in D $, if x is odd, then $ x > 0 $
(ii) $ \forall x \in D $, if x is less than 0, then x is even
(iii) $ \forall x \in D $, if x is even, then $ x \le 0 $

Q2.2

Indicate which of the following statements are true and which are false. Justify your answers as best you can:
(i) $ \forall x \in Z^+ $, $ \exists y \in Z^+ $ such that $ x = y + 1 $
(ii) $ \forall x \in Z $, $ \exists y \in Z $ such that $ x = y + 1 $
(iii) $ \exists x \in R $ such that $ \forall y \in R $, $ x = y + 1 $
(iv) $ \forall x \in R^+ $, $ \exists y \in R^+ $ such that $ xy = 1 $
(v) $ \forall x \in R $, $ \exists y \in R $ such that $ xy = 1 $
(vi) $ \forall x \in Z^+ $ and $ \forall y \in Z^+ $ $ \exists z \in Z^+ $ such that $ z = x - y $
(vii) $ \forall x \in Z $ and $ \forall y \in Z $, $ \exists z \in Z $ such that $ z = x - y $
(viii) $ \exists u \in R^+ $ such that $ \forall v \in R^+ $, $ uv < v $

Q.3 Solve both questions :

Q3.1

Prove the following:
(i) There is a real number x such that $ x > 1 $ and $ 2^x > x^{10} $.
(ii) There is an integer n such that $ 2n^2 - 5n + 2 $ is prime.

Q3.2

Disprove that for all real numbers a and b, if $ a < b $, then $ a^2 < b^2 $.

Q.4 Solve all three questions :

Q4.1

Show that $ p \vee (q \wedge r) $ and $ (p \vee q) \wedge (p \vee r) $ are logically equivalent. This is the distributive law of disjunction over conjunction.

Q4.2

Find the greatest common divisor of 414 and 662 using the Euclidean algorithm.

Q4.3

If a and b are positive integers, then prove that there exists integers s and t such that $ gcd(a,b) = sa + tb $.

Q.5 Solve both questions :

Q5.1

Use mathematical induction to prove this formula for the sum of a finite number of terms of a geometric progression with initial term a and common ratio r:
$ \sum_{j=0}^{n} ar^j = a + ar + ar^2 + \cdots + ar^n = \frac{ar^{n+1}-a}{r-1} $ when $ r \ne 1 $, where n is a non-negative integer.

Q5.2

Write short notes on the following:
(i) Forward proof
(ii) Disjunctive and conjunctive normal form
(iii) Fundamental theorem of arithmetic

Q.6 Solve both questions :

Q6.1

An odd number of people stand in a yard at mutually distinct distances. At the same time each person throws a pie at their nearest neighbour, hitting this person. Use mathematical induction to show that there is at least one survivor, that is, at least one person who is not hit by a pie.

Q6.2

Prove Bernoulli's inequality that if $ h > -1 $, then $ 1 + nh \le (1 + h)^n $ for all non-negative integers n.

Q.7 What is pigeonhole principle? Using it, prove the following:

Q7.1

What is pigeonhole principle? Using it, prove the following:
During a month with 30 days, a baseball team plays at least one game a day, but no more than 45 games. Show that there must be a period of some number of consecutive days during which the team must play exactly 14 games.

Q7.2

What is pigeonhole principle? Using it, prove the following:
The sequence 8, 11, 9, 1, 4, 6, 12, 10, 5, 7 contains 10 terms. Note that $ 10 = 3^2 + 1 $. There are four strictly increasing subsequences of length four, namely, 1, 4, 6, 12; 1, 4, 6, 7; 1, 4, 6, 10; and 1, 4, 5, 7. There is also a strictly decreasing subsequence of length four, namely, 11, 9, 6, 5.

Q.8 Solve all questions :

Q8.1

In a Round-Robin tournament, the Tigers beat the Blue Jays, the Tigers beat the Cardinals, the Tigers beat the Orioles, the Blue Jays beat the Cardinals, the Blue Jays beat the Orioles and the Cardinals beat the Orioles. Model this outcome with a directed graph.

Q8.2

Let $ G=(V,E) $ be a simple graph. Let R be the relation on V consisting of pairs of vertices (u, v) such that there is a path from u to v or such that $ u = v $. Show that R is an equivalence relation.

Q8.3

Determine whether the following given pair of directed graphs, shown in Fig. 1 and Fig. 2, are isomorphic or not. Exhibit an isomorphism or provide a rigorous argument that none exists.

Question Diagram

Q.9 Solve all questions :

Q9.1

Use pseudocode to describe an algorithm for determining the value of a game tree when both players follow a minmax strategy.

Q9.2

Suppose that $ T_1 $ and $ T_2 $ are spanning trees of a simple graph G. Moreover, suppose that $ e_1 $ is an edge in $ T_1 $ that is not in $ T_2 $. Show that there is an edge $ e_2 $ in $ T_2 $ that is not in $ T_1 $ such that $ T_1 $ remains a spanning tree if $ e_1 $ is removed from it and $ e_2 $ is added to it, and $ T_2 $ remains a spanning tree if $ e_2 $ is removed from it and $ e_1 $ is added to it.

Q9.3

Show that a degree-constrained spanning tree of a simple graph in which each vertex has degree not exceeding 2 consists of a single Hamiltonian path in the graph.


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