例7 +ax+…+a lim Im enel(4+n+…+a)-nl lim n[In(ai +a2 ++ar-InnI e x→0 而 lim nx[In(ax+a2+…+an)-mn川 ln(a1￥+…+an)-Inn nim例7 nx x n x x x n a a a           + + + → 1 1 2 1 1 lim  (1 )  [ln( ) ln ] 1 1 2 1 1 lim nx a a a n x x n x x e + + + − → =  lim [ln( ) ln ] 1 1 2 1 nx a1 a a n x n x x x e + + + − → =  lim [ln( ) ln ] 1 1 2 1 nx a1 a a n x n x x x + + + − → 而  x a a n n x n x x 1 ln( ) ln lim 1 1 1 + + − = →  ) 0 0 (