8 = 9999 add operation symbol

8 = 9999 add operation symbol

(8+8/8)*8888/8=9999

24 point operation, (8 2 1 - 3) (1 - 7 - 1 - 10)

1.（1-2）×8×（-3）=24
2.（-1-1）×（-7）-（-10）=24
How can there be negative numbers,

4 () 13 () 8 () 1 = 24 11（
4 () 13 () 8 () 1 = 2411 () 2 () 3 () 7 = 24

4+13+8-1=24
11+2×3+7=24

What is the general formula of 21 10 17

Let an = an ^ 3 + BN ^ 2 + CN + D
It's a stupid way to add a few generations, but it works

The general formula of 2, - 5,10, - 17,26
Explain the solution

Let's look at 2, 5, 10, 17, 26
2 = the square of 1 + 1
5 = the square of 2 + 1
10 = the square of 3 + 1
17 = square of 4 + 1
26 = 5 square = 1
So f (n) = n * n + 1
For 2, - 5,10, - 17,26
N + 1 degree * (n * n + 1) of F (n) = (- 1)

General formula of 0,2,5,10,17

2=1+1^2
5=1+2^2
10=1+3^2
17=1+4^2
...
When n = 1, an = 0
n> 1, an = 1 + (n-1) ^ 2

How to find the general formula of 2,5,10,17
How can I find the general formula

General term formula first see if there is equal difference, equal ratio relationship
Look at the first few "jumps" of this sequence
It depends on whether there is a power relationship
So I found out
2=1^2+1
5=2^2+1
10=3^2+1
17=4^2+1
……
So we infer the general term formula
Item n = n ^ 2 + 1
Where n ^ 2 is the square of n

Find the general formula 3 / 2,5 / 5,7 / 10,9 / 17,11 / 26

The sequence can be written as
(2*1+1)/(1^2+1) (2*2+1)/(2^2+1) .
The general formula is (2n + 1) / (n ^ 2 + 1)
You are just learning series, right? These should be accumulated gradually by yourself, learning to see the way

3 / 5 1 / 2 5 / 11 3 / 7 7 / 17

3/5=3/5
1/2=4/8
5/11=5/11
3/7=6/14
7/17=7/17
The molecules are 3, 4, one at a time, which can be written as N + 2
The denominators are 5 and 8. Each time you add 3, it can be written as 2 + 3N
So the general formula is (n + 2) / (3N + 2)

1,3,7,13,21…… General term formula

Formula = nth number = n * N-N + 1