General formula of 1 / 2 - 1 / 2 3 / 8 - 3 / 8 5 / 32 - 5 / 32

General formula of 1 / 2 - 1 / 2 3 / 8 - 3 / 8 5 / 32 - 5 / 32

The general formula of 1 / 2 - 1 / 2 3 / 8 - 3 / 8 5 / 32 - 5 / 32 An = (3 + (- 1) ^ n) * n / 2 ^ n + 1

Find the general formula 1 / 2,3 / 4,7 / 8,15 / 16,31 / 32
There is also a general formula: 2 / 3, - 1,10 / 7, - 17 / 9,26 / 11, - 37 / 13

A:
Question 1: an = (2 ^ n-1) / 2 ^ n
Question 2: an = (- 1) ^ (n + 1) * (n ^ 2 + 1) / (2n + 1)

2 8 18 32 50 128…… The general term formula of
-- it was written by the teacher anyway

72 and 98 are missing in the middle? It should be 28 18 32 50 72 98 128 If n is odd, that is, n = 2k-1 (K ≥ 1 and K is an integer), an = 2 * n ^ 2 = 2 * (2k-1) ^ 2 if n is even, that is, n = 2K (K ≥ 1 and K is an integer), an = 2 ^ (n + 1) = 2 ^

General term formula of 10101 sequence
As above

Sequence 1,0, - 1,0,1,0, - 1,0. General term formula

A2n=0,A4n+1=1,A4n+3=-1

Where is 31 ° 2'55 ″ N and 110 ° 19'43 ″ e

I looked at it on Google Earth, and it happened to be the Badong Yangtze River Bridge

@+￥=163 @-￥=19 ￥=（） @= （）

Add the two to get 2 @ = 182,
So @ = 91, ￥ = 72

A+B=163,A-B=19,A=( )B=( )

91,72

Calculation: 3 + 7 + 15 + 17 + 19 +... + 163 =?

15+17+19…… +163 should be an arithmetic sequence. Use the formula to get (74 * (15 + 163)) \ \ 2 = 6 586. Use 6586 + 3 + 7 to get 6596

5.19.65
...

When n is equal to 1, the first term is 5. When n is greater than or equal to 2, the next term is the value of the previous term multiplied by 3 plus 4 times n (where is n)