General term formula for solving strange sequence of numbers A sequence of numbers is 1,2,1,2,1,2,1,2,1,2,2,1,2... So what is the general term formula of this sequence?

General term formula for solving strange sequence of numbers A sequence of numbers is 1,2,1,2,1,2,1,2,1,2,2,1,2... So what is the general term formula of this sequence?

an=3/2＋1/2*(-1)^n
Members of the mathematics group will answer for you

Fixed point method for solving general term formula of sequence
When finding the general term formula in the form of X (n + 1) = (axn + b) / (CXN + D), we begin to find the fixed point. If there is one solution, we use the equal difference model, and there are two solutions with equal ratio. Although I am not good at expressing it, we should understand it. What if there is no solution?

Well, well, first of all, you have to understand that not all functions have fixed points, so does the sequence of numbers as a special function
If there is no solution, there are two cases. One is that there is no fixed point, so we can't find the general term in this way
2、 There is a fixed point, but the fixed point is not integral
At the same time, I suggest the student that fixed point is a method, but it is not omnipotent, and in many cases, even if it is available, it is not the best method, and the test should not be the first choice

On the solution of general term formula of periodic sequence?
Sequence: A, B, C, B, a, D, a, B, C, B, a, D, a, B, C, B, B, a, D
Find an =?
It's best to use trigonometric functions,
-1/9，1/72，7/27，1/72，-1/9，25/72,-1/9，1/72，7/27，1/72，-1/9，25/72,
The general formula an,

Cos (n π / 3) is a trigonometric function that satisfies the periodic law you want, but you also need a function
(1 / 2) - > (a), (- 1 / 2) - > (b), (- 1) - > (c), (1) - > (d)
This needs to be constructed according to the values of a, B, C and D