西安毛子科技大学导数概念XIDIAN UNIVERSITY例2设f(x)存在，求下列极限(2) I, = limh2[f(x +f(x))2h?[f(xf(xo))[f(xF(xo))2h?解 I,=limlim112h->00h-→>00h22h?Cx导数概念 解 0 1 ( ) 2 f x + =  2 2 0 0 2 1 (2) lim [ ( ) ( )] h 2 I h f x f x → h = + −0 1 ( ) 2 = f x  0 0 2 2 2 1 [ ( ) ( )] 2 lim h 1 f x f x h I h → + − = 0 0 2 2 1 [ ( ) ( )] 1 2 lim 2 1 2 h f x f x h h → + − =  例2 设 0 f x ( ) 存在，求下列极限