# Recursion: Quiz

Question 1: The use of recursion in linguistics, and the use of recursion in general, dates back to the ancient Indian linguist Pāṇini in the ________, who made use of recursion in his grammar rules of Sanskrit.
5th century BC7th century BC4th century BC6th century BC

Question 2: A familiar example is the ________ sequence: F(n) = F(n − 1) + F(n − 2).
Golden ratioEuclidean algorithmPell numberFibonacci number

Question 3: For example, the formal definition of the ________ in set theory follows: 0 is a natural number, and each natural number has a successor, which is also a natural number.
Cardinal numberIntegerNatural numberReal number

Question 4: Another interesting example is the set of all true "reachable" propositions in an ________.
Axiomatic systemSet theoryGeorg CantorMathematical logic

Question 5: One example application of recursion is in ________ for programming languages.
Compiler-compilerBottom-up parsingCompilerParsing

Question 6: ________: C0 = 1, Cn + 1 = (4n + 2)Cn / (n + 2)
Binomial coefficientFactorialCombinatoricsCatalan number

Question 7: A famous recursive function is the ________ which, unlike the Fibonacci sequence, cannot be expressed without recursion.
FactorialPrimitive recursive functionAckermann functionAlgorithm

Question 8: In ________, this is a theorem guaranteeing that recursively defined functions exist.
Set theoryModel theoryGeorg CantorMathematical logic

Question 9: The ________ is a classic example of recursion:
Pell numberGolden ratioEuclidean algorithmFibonacci number

Question 10: As a ________ technique, this is called divide and conquer and is key to the design of many important algorithms.
Software designRequirements analysisComputer programmingSoftware testing