余和: 1 十 十 十 (n+1)!(n+2)! (n+1)!n+2 ≤ 十 十 n n+1(m+1)2× nh 欲使r≤103,只要,≤103, 即nn!≥105,而88=322560>10 e≈1+1+++…+,≈271828 2!3 上一页下一页返回余和: + + + +  ( 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 = 欲使 r n  10−5 , 只要 10 , ! 1 −5  n n 8! 1 3! 1 2! 1 e  1+ 1+ + ++  2.71828 ! 10 , 5 n n  8 8! 322560 10 , 5 即 而  = 