VE>0,X>0,wx:||>X→f(x)-4<E 换一种说法: lim f(=A means x→0 VE>0彐X>0 x∈(-∞,-X∪(X,+∞) 8<f(x)<A+e September. 2004September, 2004 0 − − + x X X ( , ) ( , ) − + A f x A ( ) X 0 换一种说法: lim ( ) means x f x A → = − 0, 0 , : ( ) X x x X f x A