Generating Functions
This quiz is designed to assess your understanding of generating functions, a powerful tool used to solve various problems in combinatorics and probability.
Questions
What is the generating function for the sequence (1, 2, 3, 4, \dots)?
- \(\frac{x}{1-x}\)
- \(\frac{x}{(1-x)^2}\)
- \(\frac{x^2}{1-x}\)
- \(\frac{x^2}{(1-x)^2}\)
Find the generating function for the sequence (1, 1, 2, 3, 5, 8, \dots), where each term is the sum of the previous two terms.
- \(\frac{x}{1-x-x^2}\)
- \(\frac{x}{1-2x+x^2}\)
- \(\frac{x}{1-x+x^2}\)
- \(\frac{x}{1+x+x^2}\)
What is the generating function for the sequence (1, 2, 4, 8, 16, \dots)?
- \(\frac{x}{1-2x}\)
- \(\frac{x}{1-x^2}\)
- \(\frac{x}{1-3x}\)
- \(\frac{x}{1-4x}\)
Find the generating function for the sequence (1, 3, 6, 10, 15, \dots), where each term is the sum of the first (n) positive integers.
- \(\frac{x}{(1-x)^3}\)
- \(\frac{x}{(1-x)^2}\)
- \(\frac{x}{(1-x)}\)
- \(\frac{x}{1-x+x^2}\)
What is the generating function for the sequence (1, 4, 9, 16, 25, \dots)?
- \(\frac{x}{1-x^2}\)
- \(\frac{x}{1-2x^2}\)
- \(\frac{x}{1-3x^2}\)
- \(\frac{x}{1-4x^2}\)
Find the generating function for the sequence (1, 2, 4, 7, 11, \dots), where each term is the sum of the first (n) odd positive integers.
- \(\frac{x}{(1-x)^4}\)
- \(\frac{x}{(1-x)^3}\)
- \(\frac{x}{(1-x)^2}\)
- \(\frac{x}{(1-x)}\)
What is the generating function for the sequence (1, 3, 5, 7, 9, \dots)?
- \(\frac{x}{1-x^3}\)
- \(\frac{x}{1-2x^3}\)
- \(\frac{x}{1-3x^3}\)
- \(\frac{x}{1-4x^3}\)
Find the generating function for the sequence (1, 4, 9, 16, 25, \dots), where each term is the square of the first (n) positive integers.
- \(\frac{x}{(1-x)^5}\)
- \(\frac{x}{(1-x)^4}\)
- \(\frac{x}{(1-x)^3}\)
- \(\frac{x}{(1-x)^2}\)
What is the generating function for the sequence (1, 2, 6, 24, 120, \dots)?
- \(\frac{x}{1-x-x^2-x^3}\)
- \(\frac{x}{1-2x-x^2-x^3}\)
- \(\frac{x}{1-3x-x^2-x^3}\)
- \(\frac{x}{1-4x-x^2-x^3}\)
Find the generating function for the sequence (1, 3, 6, 10, 15, \dots), where each term is the sum of the first (n) triangular numbers.
- \(\frac{x}{(1-x)^4}\)
- \(\frac{x}{(1-x)^3}\)
- \(\frac{x}{(1-x)^2}\)
- \(\frac{x}{(1-x)}\)
What is the generating function for the sequence (1, 5, 14, 30, 55, \dots)?
- \(\frac{x}{1-x-x^2}\)
- \(\frac{x}{1-2x-x^2}\)
- \(\frac{x}{1-3x-x^2}\)
- \(\frac{x}{1-4x-x^2}\)
Find the generating function for the sequence (1, 4, 10, 20, 35, \dots), where each term is the sum of the first (n) square numbers.
- \(\frac{x}{(1-x)^5}\)
- \(\frac{x}{(1-x)^4}\)
- \(\frac{x}{(1-x)^3}\)
- \(\frac{x}{(1-x)^2}\)
What is the generating function for the sequence (1, 2, 5, 12, 22, \dots)?
- \(\frac{x}{1-x-x^2-x^3}\)
- \(\frac{x}{1-2x-x^2-x^3}\)
- \(\frac{x}{1-3x-x^2-x^3}\)
- \(\frac{x}{1-4x-x^2-x^3}\)
Find the generating function for the sequence (1, 5, 15, 35, 70, \dots), where each term is the sum of the first (n) pentagonal numbers.
- \(\frac{x}{(1-x)^6}\)
- \(\frac{x}{(1-x)^5}\)
- \(\frac{x}{(1-x)^4}\)
- \(\frac{x}{(1-x)^3}\)