余和: 1 十 十 (1 十 (n+1)!(n+2)! (n+1)!n+2 1 1 ≤ 十 十 (n+1)!n+1(n+12 n 欲使r≤105,只要,≤1035, n·n 即nm≥105,而88!=322560>10 11 e≈1+1+++…+,≈2.71828 2!3! 8 上页余和: + + + +  ( 2)! 1 ( 1)! 1 n n rn ) 2 1 (1 ( 1)! 1 + + + + = n n ) ( 1) 1 1 1 (1 ( 1)! 1 2 + + + + + +  n n n ! 1 n n = 10 , −5 欲使 rn  10 , ! 1 −5  n n 只要 ! 10 , 5 即n n  8 8! 322560 10 , 5 而  =  8! 1 3! 1 2! 1 e  1+ 1+ + ++  2.71828