Mathematical Sequences and Arrays Quiz
Quiz covering Riordan arrays, the Fibonacci sequence, golden ratio, and Pascal triangle, exploring their properties, generating functions, and relationships.
Questions
What is a Riordan array?
- A triangular array of numbers where each entry is the sum of the two entries above it.
- A triangular array of numbers where each entry is the product of the two entries above it.
- A triangular array of numbers where each entry is the difference of the two entries above it.
- A triangular array of numbers where each entry is the quotient of the two entries above it.
What is the generating function of a Riordan array?
- $$f(x) = \sum_{n=0}^\infty a_n x^n$$
- $$f(x) = \prod_{n=0}^\infty a_n x^n$$
- $$f(x) = \sum_{n=0}^\infty a_n x^{-n}$$
- $$f(x) = \prod_{n=0}^\infty a_n x^{-n}$$
What is the recurrence relation for a Riordan array?
- $$a_n = a_{n-1} + a_{n-2}$$
- $$a_n = a_{n-1} * a_{n-2}$$
- $$a_n = a_{n-1} - a_{n-2}$$
- $$a_n = a_{n-1} / a_{n-2}$$
What is the most well-known example of a Riordan array?
- The Fibonacci sequence
- The Pascal triangle
- The Catalan numbers
- The Stirling numbers of the second kind
What are some applications of Riordan arrays?
- Counting
- Probability
- Number theory
- All of the above
What is the generating function of the Fibonacci sequence?
- $$f(x) = \frac{x}{1-x-x^2}$$
- $$f(x) = \frac{x}{1-x+x^2}$$
- $$f(x) = \frac{x}{1+x-x^2}$$
- $$f(x) = \frac{x}{1+x+x^2}$$
What is the recurrence relation for the Fibonacci sequence?
- $$a_n = a_{n-1} + a_{n-2}$$
- $$a_n = a_{n-1} * a_{n-2}$$
- $$a_n = a_{n-1} - a_{n-2}$$
- $$a_n = a_{n-1} / a_{n-2}$$
What are the first few terms of the Fibonacci sequence?
- 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, ...
- 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, ...
- 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, ...
- 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, ...
What is the closed form of the $n$th Fibonacci number?
- $$F_n = \frac{\phi^n - \psi^n}{\sqrt{5}}$$
- $$F_n = \frac{\phi^n + \psi^n}{\sqrt{5}}$$
- $$F_n = \frac{\phi^n - \psi^n}{\sqrt{5}} + 1$$
- $$F_n = \frac{\phi^n + \psi^n}{\sqrt{5}} + 1$$
What is the golden ratio?
- $$\phi = \frac{1 + \sqrt{5}}{2}$$
- $$\phi = \frac{1 - \sqrt{5}}{2}$$
- $$\phi = \frac{\sqrt{5} + 1}{2}$$
- $$\phi = \frac{\sqrt{5} - 1}{2}$$
What is the relationship between the golden ratio and the Fibonacci sequence?
- The limit of the ratio of consecutive Fibonacci numbers is the golden ratio.
- The golden ratio is the average of two consecutive Fibonacci numbers.
- The golden ratio is the square root of the sum of two consecutive Fibonacci numbers.
- The golden ratio is the product of two consecutive Fibonacci numbers.
What are some applications of the golden ratio?
- Art and design
- Architecture
- Nature
- All of the above
What is the Pascal triangle?
- A triangular array of numbers where each entry is the sum of the two entries above it.
- A triangular array of numbers where each entry is the product of the two entries above it.
- A triangular array of numbers where each entry is the difference of the two entries above it.
- A triangular array of numbers where each entry is the quotient of the two entries above it.
What is the generating function of the Pascal triangle?
- $$f(x) = \frac{1}{1-x-x^2}$$
- $$f(x) = \frac{1}{1-x+x^2}$$
- $$f(x) = \frac{1}{1+x-x^2}$$
- $$f(x) = \frac{1}{1+x+x^2}$$
What is the recurrence relation for the Pascal triangle?
- $$a_n = a_{n-1} + a_{n-2}$$
- $$a_n = a_{n-1} * a_{n-2}$$
- $$a_n = a_{n-1} - a_{n-2}$$
- $$a_n = a_{n-1} / a_{n-2}$$