1,1,2,3,5,8,13,12......
number21=10946 i need to know what 22 is
2006-11-29 14:20:57 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
That last number should be 21.
That sequence is called the Fibonacci sequence. It's the most famous sequence probably ever.
The 22nd is 17711. You can look it up in table...or there's actually a way to compute it without having to do all the ones up to 22.
The formula for the nth Fibonacci number is:
F(n) = 1/sqrt(5) [((1+sqrt(5))/2)^n + ((1-sqrt(5))/2)^n]
Kind of messy, but easier than writing them all out up to 22.
2006-11-29 14:24:21 · answer #1 · answered by Jim Burnell 6 · 1⤊ 0⤋
Check that last number...I think you typed it incorrectly.
The sequence 1, 1, 2, 3, 5, 8, 13, 21, 34, ... is the famous Fibonacci Sequence, where each term is the sum of the previous two terms (that is, the third term, 2, is equal to 1 + 1. 13 = 8 + 5, etc.).
Are you given what the 20th term is? If not, you have a bit of adding to do. Just follow the simple pattern.
(There is a way to find the 22nd term directly using the golden mean, but that's probably more advanced than you're looking for.)
2006-11-29 15:04:28 · answer #2 · answered by Kevin W 2 · 0⤊ 0⤋
Assuming the 12 was a typo for 21, the 22nd term is 17711. Its the fibonacci sequence - add the last two terms to get the next.
2006-11-29 14:24:33 · answer #3 · answered by stephen m 4 · 0⤊ 0⤋
nnw u r write it is a fibnocci series
to know nth no. of this sreis u must add previous two no.s
therefore u must all the no. of series 1-20
i.e
1
1
2
3
5
8
13
21
34
55
89
144
233
377
610
987
1597
2584
4181
6765
10946
17711
hence the answer is 17711
2006-11-29 14:36:15 · answer #4 · answered by sidharth 2 · 0⤊ 0⤋
That is Fibonacci's series if the last 12 is really a 21... each number is obtained by adding the previous two numbers. It was constructed by Fibonacci in the XV century in Venice. One more reason to know Italy :-)
2006-11-29 14:23:31 · answer #5 · answered by nnvv02 2 · 1⤊ 0⤋
17711
It's the Fibonacci sequence, but the last number you gave should be 21, not 12.
2006-11-29 14:24:21 · answer #6 · answered by Keith P 7 · 0⤊ 0⤋
I don't think this pattern is correct. It appears that you add the first two number and arrive at the third, the second and third and arrive at the fourth, and so on. The problem appears to be flawed where you have the number twelve (?). So I'm not sure how to continue.
2006-11-29 14:24:59 · answer #7 · answered by rutheo 2 · 0⤊ 0⤋
1,1,2,3,5,8,13 well that pat is the fibonnacci sequence, and the next number (12) that you have on there doenst make sense
but if we assume that its the fibb sequence
then it will equal...
17711
2006-11-29 14:25:52 · answer #8 · answered by The Russian 2 · 1⤊ 0⤋