lim f(x)=a x→>x Va>o 彐δ>0 x:0<x-x0<→f(x)-A<6 分VE>0,3δ>0, vx:0<x-x0<6→a(x)<E lima(x=o a(x)=f(x-a) x→> 分冷a(x)=f(x)-A是无穷小 分>f(x)=A+a(x)a(x)是无穷小 October 2004October, 2004 0 lim ( ) x x f x A → =  0 , ( 0, ) 0 x x x : 0 f x A           −    −  0 0, ) , : 0 ( 0 x x x x            −     ((x f x A ) ) = ( − ) 0 lim 0 ( ) x x  x → =  ( ) ( ) x f x A = − 是无穷小  f x A x ( ) ( ) = + α(x) 是无穷小