) 中图学技术大荸学系 University of Science and Technology of China DEPARTMENT OF MATHEMATICS (2)若: A=2>4|2…24,1=-2 k (k) a,v,+a V十∴十a 则k足够大时,有 (k) 1(a,v,+a2(1)v2) 所以:x(2k+2)/x(2)≈22 (2k+1)/(2k-1 所以 k+1) 人x (k) 2≈y(k+1) 入x (k)数 学 系 University of Science and Technology of China DEPARTMENT OF MATHEMATICS （2）若： 1 2 3 1 2  =     n , = − ( )                 = + − + + n k n n k k k x a v a v a v 1 1 1 1 2 2 ( ) 1     ( ( ) ) 1 1 1 2 2 ( ) x a v a 1 v k k k   + − 则k足够大时，有 2 1 (2 1) (2 1) 2 1 (2 2) (2 ) / /     + − + k k k k x x x x 所以： ( ) 1 ( 1) 2 ( ) 1 ( 1) 1 k k k k v x x v x x    −  + + 所以： +