Answer:46368
Explanation:
Start with two non-negative integers, f(0) and f(1). Compute f(2) = f(0) + f(1). Compute f(3) = f(1) + f(2).
Continue, creating f(n) = f(n-1) + f(n-2), where each new number is the sum of the prior two numbers in the sequence.
By convention, f(0) = 0. f(1) = 1 for our new first pair. f(2) = 1 as well, as conception just occurred. The new pair is born at the end of month 2, so during month 3, f(3) = 2. Only the initial pair produces offspring in month 3, so f(4) = 3. In month 4, the initial pair and the month 2 pair breed, so f(5) = 5. At the end of a year, Fibonacci has 144 pairs of rabbits.
1st month=1
2nd month = 1
3rd month= 1+1=2
4th month=2+1=3
5th month= 3+2=5
6th month =5+3 =8
7th month= 8+5 =13
8th month = 13+8 =21
9th month =21+13 =34
10th month= 34+21 =55
11th month =55+34=89
12th month=89+55=144
13th month =144+89=233
14th month= 233+144= 377
15th month=377+233= 610
16th month = 610+377=987
17th month =987+610 =1597
18th month =1597+987 =2584
19th Month =2584+1597= 4181
20th month =4281 + 1597= 6765
21st month =6765+ 4181= 10946
22nd month= 6765+10946= 17711
23rd month= 17711+ 10946= 28657
24th month = 28657+ 17711= 46368
Therefore side length of the field at the end of 2 years is 46368
