Tribhuvan University
Institute of Science and Technology
2080-new
Bachelor Level / second-semester / Science
Computer Science and Information Technology( CSC165 )
Discrete Structure
Full Marks: 60 + 20 + 20
Pass Marks: 24 + 8 + 8
Time: 3 Hours
Candidates are required to give their answers in their own words as far as practicable.
The figures in the margin indicate full marks.
SECTION A
Attempt any TWO question.
How can you use mathematical induction to prove statements? Use mathematical induction to show that sum of first n positive integer is
$$\frac{{n(n + 1)}}{{2}}$$
Explain linear homogeneous recurrence relation with constant coefficients. What is the solution of the recurrence relation an = 6an-1 – 9an-2 with initial conditions a0 = 1 and a1 = 6?
What is shortest path problem? Use Dijkstra’s shortest path algorithm to find the shorteszt path between vertices a and z in the weighted graph below:
SECTION B
Attempt any EIGHT question.
Let us assume tha R be a relation on the set of ordered pair of positive integers such that ((a, b), (c, d)) ∈ R if and only if ad = bc. Is R an equivalence relation?
Define function. Let f1 and f2 be function from R to R such that f1(x) = x2 and f2(x) = x – x2 . What are the functions f1 + f2 and f1 . f2?
Explain fuzzy set with example. How do you find complement of a fuzzy set?
What is congurent modulo? Determine whether 37 is congurent to 3 modulo 7 and wheather -29 is congurent to 5 modulo 17.
Define network flow with example. What are saturated edge, unsaturated edge and slack value?
Give an example of tautology and contradiction. Show that implication and contrapositive are equivalence.
What is direct proof ? Give a direct proof that if m and n are both perfect squares, then mn is also a perfect square.
What is product rule? How many strings are there of four lowercase letters that have the letter x in them?
Explain the matrix representation of relations with example.