VE>0.38>0 Wx:0<x-x<→|(x)-4<E 换一种说法:limf(x)=A VE>0彐δ>0 x∈(x0-d,x0)∪(x,x0+) →A-E<f(x)<A+E September. 2004September, 2004 0 0, 0 x x x f x A : 0 ( ) − − 0 0 0 0 0 − + x x x x x ( , ) ( , ) − + A f x A ( ) 0 换一种说法: 0 lim ( ) x x f x A → =