? -Introduction to Fibonacci sequence

Almost everyone has to go up the steps every day, and there may be quite a few steps a day. This is the problem. Suppose there are 1 2 steps from the1floor to the second floor. Due to the height of the steps, we can only go up 1 or 2 steps at a time (by default, we can only go from 0 to 1 at first). How many ways are there to get from 1 floor to the second floor? In fact, many people have questioned this question.

To understand this problem, we must first understand what Fibonacci sequence is. Fibonacci is a mathematician, and Fibonacci series is a series obtained from the rabbit problem mentioned by Fibonacci in the abacus. This series is 1, 1, 2, 3, 5, 8, 13, 2 1, 34 ... In fact, this series appeared in the first volume of the sixth grade mathematics textbook of Qingdao Edition. It is not difficult to find that Fibonacci sequence satisfies the following characteristics: the first two terms are 1, and from the third term, each term is the sum of the first two terms. It can be described in mathematical symbolic language as (n is a natural number):

Therefore, it is not difficult to see that the sequence of upstairs method coincides with Fibonacci sequence, namely 1, 1, 2, 3, 5, 8, 13, 2 1, 34 ..., so we can get that the twelfth term of Fibonacci sequence is up to 65438. Then how many ways can you get to the third floor and the first *** 18 steps?

Fibonacci sequence has great vitality, because it has unexpected functions! Which is math. Maybe you don't know that when you feel useless, the mathematics you have learned is quietly changing your life. At some point in the future, you will be surprised to find that mathematics is really useful!

? "Mathematics is the word God used to write the universe-Galileo"

Life is full of mathematics, as long as you have a pair of thinking eyes, you will definitely see a different world!

Attached:

1. Why RMB 1 yuan, 2 yuan and 5 yuan, but not 3 yuan and 7 yuan?

2. How to fingerprint the mobile phone?

3. How is the mobile phone accurately located?

4. What does the question "1+ 1" mean?

5. What is cyclodialysis?

6. Can you write the word "Tian" in one stroke? Why? To the tourist attractions, can you plan a road to visit all the scenic spots? )

7. Why is the price of the same dish in the vegetable market the same for different vendors?

8. Why is driving often blocked?