3.对数函数f(x)=log。x(a>0,a≠1)的导数 由导数定义 log1+ y'=lim log (x+h)-logx lim h-→0 h -→0 h X I log.(og. 1 xh-→0 xIna 极秋私 (o. (nx)'= 1-x #( ) log ( 0, 1) . a 3. 对数函数 f x x a a =   的导数 h x h x y a a h log ( ) log lim 0 + −  = → 1 (log ) ln a x x a  = x x h x h a h 1 log (1 ) lim 0  + = → h x a h x h x lim log (1 ) 1 0 = + → 1 1 log . ln a e x x a = = 1 (ln ) x x  = 由导数定义 #