(2)lim(1+ e 定义lim(1+-)"=e n 设xn=(1+ n 1 n(n =1+·二 n(n-1)…(n-n+1)1 十∴ 2!n2 n n =1+1+(1--)+…+,(1--)(1--)…(1- 1. n n 上页(2) e x x x + = → ) 1 lim(1 定义 e n n n + = → ) 1 lim(1 n n n x ) 1 设 = (1 +  + − = +  + 2 1 2! 1 ( 1) 1! 1 n n n n n ). 1 ) (1 2 )(1 1 (1 ! 1 ) 1 (1 2! 1 1 1 n n n n n n − = + + − ++ − −  − n n n n n n n 1 ! ( 1) ( 1)  − − + + 