Recurrence Relations

This quiz covers fundamental concepts and techniques related to recurrence relations, a core topic in combinatorics and discrete mathematics.

14 Questions Published

Questions

Question 1 Multiple Choice (Single Answer)

What is the general form of a linear homogeneous recurrence relation of order k?

  1. a_n = c_1 * a_{n-1} + c_2 * a_{n-2} + ... + c_k * a_{n-k}
  2. a_n = c_1 * a_{n-1} + c_2 * a_{n-2} + ... + c_k * a_{n+k}
  3. a_n = c_1 * a_{n+1} + c_2 * a_{n+2} + ... + c_k * a_{n+k}
  4. a_n = c_1 * a_{n-1} + c_2 * a_{n-2} + ... + c_k * a_{n-1}
Question 2 Multiple Choice (Single Answer)

Which of the following is a characteristic equation for the recurrence relation a_n = 3 * a_{n-1} - 2 * a_{n-2}?

  1. r^2 - 3 * r + 2 = 0
  2. r^2 + 3 * r + 2 = 0
  3. r^2 - 3 * r - 2 = 0
  4. r^2 + 3 * r - 2 = 0
Question 3 Multiple Choice (Single Answer)

What is the general solution to the recurrence relation a_n = 3 * a_{n-1} - 2 * a_{n-2} with initial conditions a_0 = 1 and a_1 = 2?

  1. a_n = 2^n + 1
  2. a_n = 2^n - 1
  3. a_n = 3^n + 1
  4. a_n = 3^n - 1
Question 4 Multiple Choice (Single Answer)

Which of the following is a recurrence relation for the Fibonacci sequence?

  1. F_n = F_{n-1} + F_{n-2}
  2. F_n = F_{n-1} - F_{n-2}
  3. F_n = 2 * F_{n-1} - F_{n-2}
  4. F_n = 2 * F_{n-1} + F_{n-2}
Question 5 Multiple Choice (Single Answer)

What is the generating function for the sequence {1, 2, 4, 8, 16, ...}?

  1. G(x) = 1 / (1 - 2 * x)
  2. G(x) = 1 / (1 + 2 * x)
  3. G(x) = 1 / (1 - 4 * x)
  4. G(x) = 1 / (1 + 4 * x)
Question 6 Multiple Choice (Single Answer)

Which of the following is a recurrence relation for the number of ways to climb n stairs, if you can take either one step or two steps at a time?

  1. f(n) = f(n-1) + f(n-2)
  2. f(n) = f(n-1) - f(n-2)
  3. f(n) = 2 * f(n-1) - f(n-2)
  4. f(n) = 2 * f(n-1) + f(n-2)
Question 7 Multiple Choice (Single Answer)

What is the asymptotic behavior of the solution to the recurrence relation a_n = 2 * a_{n-1} - 3 * a_{n-2} as n approaches infinity?

  1. a_n ~ 2^n
  2. a_n ~ 3^n
  3. a_n ~ (-2)^n
  4. a_n ~ (-3)^n
Question 8 Multiple Choice (Single Answer)

Which of the following is a recurrence relation for the number of ways to partition a set of n elements into k non-empty subsets?

  1. S(n, k) = S(n-1, k) + S(n-1, k-1)
  2. S(n, k) = S(n-1, k) - S(n-1, k-1)
  3. S(n, k) = 2 * S(n-1, k) - S(n-1, k-1)
  4. S(n, k) = 2 * S(n-1, k) + S(n-1, k-1)
Question 9 Multiple Choice (Single Answer)

What is the generating function for the sequence {1, 1, 2, 3, 5, 8, 13, ...}, where each term is the sum of the two previous terms?

  1. G(x) = 1 / (1 - x - x^2)
  2. G(x) = 1 / (1 + x + x^2)
  3. G(x) = 1 / (1 - x + x^2)
  4. G(x) = 1 / (1 + x - x^2)
Question 10 Multiple Choice (Single Answer)

Which of the following is a recurrence relation for the number of ways to make change for n cents using coins of denominations 1, 5, and 10 cents?

  1. C(n) = C(n-1) + C(n-5) + C(n-10)
  2. C(n) = C(n-1) - C(n-5) - C(n-10)
  3. C(n) = 2 * C(n-1) - C(n-5) + C(n-10)
  4. C(n) = 2 * C(n-1) + C(n-5) - C(n-10)
Question 11 Multiple Choice (Single Answer)

What is the asymptotic behavior of the solution to the recurrence relation a_n = 3 * a_{n-1} - 2 * a_{n-2} as n approaches infinity?

  1. a_n ~ 3^n
  2. a_n ~ 2^n
  3. a_n ~ (-3)^n
  4. a_n ~ (-2)^n
Question 12 Multiple Choice (Single Answer)

Which of the following is a recurrence relation for the number of ways to arrange n distinct objects in a row?

  1. P(n) = P(n-1) + 1
  2. P(n) = P(n-1) - 1
  3. P(n) = 2 * P(n-1) + 1
  4. P(n) = 2 * P(n-1) - 1
Question 13 Multiple Choice (Single Answer)

What is the generating function for the sequence {1, 4, 9, 16, 25, ...}?

  1. G(x) = 1 / (1 - 4 * x)
  2. G(x) = 1 / (1 + 4 * x)
  3. G(x) = 1 / (1 - 2 * x)
  4. G(x) = 1 / (1 + 2 * x)
Question 14 Multiple Choice (Single Answer)

Which of the following is a recurrence relation for the number of ways to color n balls using k colors, if each ball can be colored with any of the k colors?

  1. C(n, k) = C(n-1, k) + C(n-1, k-1)
  2. C(n, k) = C(n-1, k) - C(n-1, k-1)
  3. C(n, k) = 2 * C(n-1, k) + C(n-1, k-1)
  4. C(n, k) = 2 * C(n-1, k) - C(n-1, k-1)