A2 is 1.5 a3 is -0.5 a4 is 1.5.

a2= 1-(-0.5)= 1.5

a3= 1- 1.5=-0.5

a4= 1-(-0.5)= 1.5

(2)a 1000= 1.5

a 100 1=-0.5

I hope I can help the landlord and hope that the landlord will adopt it. It took me a long time to do it. 6、a2 = 1/( 1-a 1)= 1/( 1+ 1/2)= 2/3；

a3 = 1/( 1-a2)= 1/( 1-2/3)= 3；

a4 = 1/( 1-a3)= 1/( 1-3)=- 1/2 = a 1；

So A5 =1(1-A4) =1(1-a1) = A2;

a6 = 1/( 1-a5)= 1/( 1-a2)= a3；

...

∴a 1=a4=a7=a 10=…=a 1000=- 1/2

A2 = A5 = A8... 1, I think my egg hurts. Look, my egg hurts, 1, (1) because every number is equal to the reciprocal of the difference between 1 and the number before it.

therefore

Bring a 1=- 1/2 into A2 =11-a1.

A2=2 /3 a3=3 a4=- 1/2。

(2) Because it is a cycle with a period of 3 ~.

A1000 =-1/2a1001= 2/3,0, a mathematical problem about letters. I give high marks. )

(Note: a 1 a2 a3 ... is not a power of A, but in the lower right corner of A, not the upper right corner. )

If there are several numbers, write them as follows: a 1, a2, a3, ... Ann.

Article: A2 =11-A2.an =11-an-1.

If given: a 1=- 1/2.

(1) Find the values of A2, A3 and A4. Not too complicated. Write the formula clearly so that I can understand it.

(2) Find the values of a 1000 and a 100 1.