maths.free › Number Theory › Sequences

Sequences

Fibonacci, recurrences and closed forms.

A sequence defined by a rule from earlier terms is a recurrence. The Fibonacci numbers are the classic: each is the sum of the previous two. Many recurrences have a closed form, for Fibonacci it involves the golden ratio, but computing them term by term is often the clearest path.

Delovni primer · fib(20)

Fib(20)

20

Korak po koraku

  1. F_0 = 0,; F_1 = 1

    Each Fibonacci number is the sum of the two before it.

  2. F_{2} = F_{1} + F_{0} = 1

  3. F_{3} = F_{2} + F_{1} = 2

  4. F_{4} = F_{3} + F_{2} = 3

  5. F_{5} = F_{4} + F_{3} = 5

  6. F_{6} = F_{5} + F_{4} = 8

  7. F_{7} = F_{6} + F_{5} = 13

  8. F_{8} = F_{7} + F_{6} = 21

  9. \vdots

  10. F_{19} = F_{18} + F_{17} = 4181

  11. F_{20} = F_{19} + F_{18} = 6765

Odkrij odgovor
F_{20} = 6765

Zdaj pa ti. Izberite problem, ali tipkajte ali narišite svojo. Vsak korak, sliko, odgovor skriti, dokler ne vprašate.

Obdrži svoje delo.

Brezplačen račun dodaja opombe o vsaki lekciji, zapis o tem, kar ste končali, vaše rešene težave na enem mestu, in tutor lahko vprašate o tej strani. Sama matematika je odprta za vse, prijavljena ali ne.

Registriraj se Prijava

Simboli, ki se uporabljajo tukaj

Tapnite vsak simbol za popolno opredelitev, sliko in kaj pomeni vsaka črka v njej.

Kako: Sequences

  1. Each Fibonacci number is the sum of the two before it.

Vprašanja, ki jih ljudje sprašujejo

Why are primes so important?

Every integer factors into primes in exactly one way, so primes are the atoms of multiplication. Cryptography relies on that factoring being easy to state and hard to do.

How do I tell whether a big number is prime?

Trial division up to the square root works for small numbers. For large ones, probabilistic tests (Miller-Rabin) give an answer that is wrong with negligible probability, and deterministic tests (AKS) exist but are slower.

Več v Number Theory