BS Artificial Intelligence · Semester 1 · Assignment 03 · Weeks 9–12

Discrete Mathematics for BSAI

Sequences, Recurrences and Counting Choices

Dr. Hira Benish
Associate Professor & HoD, Mathematics
PMAI Lab, Mathematics Behind AI

Assignment 03 · Weeks 9–12Begin  

01 · Assignment Overview

Separate term values from totals and choose the right counting method for a small feature-selection system. Complete after Week 12.

Coverage
Weeks 9–12
Points
25
Estimated work
75–90 minutes

Instructions: Show the mathematical steps and explain each conclusion in one or two sentences. State any assumption you use. Hand reasoning and diagrams are required; Python or Colab may check a prediction but cannot replace the argument. Write your name and roll number on the first page.

Submission: One readable PDF of your own written or typed work, with pages in question order. Include diagrams and tables where requested. The instructor will announce the date and course-grade weight separately; the 25 points below describe only this assignment's internal rubric.

Interpretation: Counting feature sets tells us how many candidates there are. It does not identify which set predicts well.

02 · Questions

Q1 · Sequence versus sum 5 points

A weekly activity log begins 4, 7, 10, 13, … entries.

  1. State the next two terms and a formula for aₙ with n starting at 1. (3)
  2. Find the total entries in the first six weeks, using a finite sum. Explain why the sixth term is not the total. (2)

Q2 · A recurrence model 5 points

A toy queue begins at b₁=2 and follows bₙ=2bₙ₋₁+1 for n≥2.

  1. Compute b₂,b₃,b₄,b₅, showing each substitution. (4)
  2. State one real-world limitation of treating this update rule as an accurate queue model. (1)

Q3 · Exploring possible feature sets 10 points

A team lists six distinct candidate features: A attendance, Q quiz result, S study hours, P practice count, T tutorial attendance, and R previous score. It plans a three-feature set. Assume all selections are allowed unless a restriction is explicitly stated.

  1. How many three-feature sets are possible? Explain why order does not matter. (3)
  2. If the team ranks first, second and third distinct features, how many ordered rankings are possible? (2)
  3. How many three-feature sets must include A? (2)
  4. How many three-feature sets do not contain both A and Q together? Count and justify the excluded sets. (3)

Q4 · Overlap and a guarantee 5 points

Among 24 students, 12 attended a mathematics workshop, 11 attended a Python workshop, and 4 attended both. In a separate group, 13 students have birth months among the 12 calendar months.

  1. How many attended at least one workshop? How many attended neither? Show the overlap adjustment. (3)
  2. What repetition is guaranteed in the separate birth-month group? Explain in one sentence. (2)

03 · Submission Checklist

  • Distinguish a₆ from the sum through week 6.
  • Show the initial value in every recurrence trace.
  • For each feature count, justify whether order and restrictions matter.
  • Explain overlap subtraction and the guarantee, not only the numbers.

Mark distribution: 5 + 5 + 10 + 5 = 25. Optional enumeration in Colab may verify a small answer after the hand count.