精选问答
AMC12的题目The Fibonacci sequence starts with two 1s, and each term afterwards is the sum of its two predecessors. Which one of the ten digits is the last to appear in the units position of a number in the Fibonacci sequence?答案是6,有详解,但是没看懂.这个到底是让干什么的?

2019-05-28

AMC12的题目
The Fibonacci sequence starts with two 1s, and each term afterwards is the sum of its two predecessors. Which one of the ten digits is the last to appear in the units position of a number in the Fibonacci sequence?
答案是6,有详解,但是没看懂.这个到底是让干什么的?
优质解答
斐波那契序列的公式是A(n)=A(n-1)+A(n-2)
即,如果开始的两个数字是1,1,那么第3个数就是两个1之和2,第4个数字是第2个和第3个数字之和5,依次类推.序列应该是1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,1597,2584,4181,6765,10946,...
本题问0-9这10个数字中,哪一个最后出现在序列数字的个位上?显然是6.
更简单的算法是只加个位,十位以上全不看,序列如下:
1
2
3
5
8
3
1
4
5
9
4
3
7
0
7
7
4
1
5
6
斐波那契序列的公式是A(n)=A(n-1)+A(n-2)
即,如果开始的两个数字是1,1,那么第3个数就是两个1之和2,第4个数字是第2个和第3个数字之和5,依次类推.序列应该是1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,1597,2584,4181,6765,10946,...
本题问0-9这10个数字中,哪一个最后出现在序列数字的个位上?显然是6.
更简单的算法是只加个位,十位以上全不看,序列如下:
1
2
3
5
8
3
1
4
5
9
4
3
7
0
7
7
4
1
5
6
相关问答