二、函数的和、差、积、商的求导法则 定理1设f(x),g(都在点可导,则它们的和、 差、积、商(除分母为零的点外)都在x点可导,且 [f(x)±g(x)订=f(x)±g(x) (1) [f(x)g(x)]=f'(x)g(x)+f(x)g'(x) (2) [器-G g(x)≠0(3) [g(x)] 推论1[Cf(x)]=Cf'(x)(C为常数)。二、函数的和、差、积、商的求导法则 差、积、商(除分母为零的点外)都在 f x g x ( ), ( ) x x f x g x f x g x ( ) ( ) ( ) ( ) = f x g x f x g x f x g x ( ) ( ) ( ) ( ) ( ) ( ) = + ( ) ( ) ( ) ( ) ( ) ( ) ( ) 2 f x f x g x f x g x g x g x − = g x( ) 0 定理1 设 都在 点可导,则它们的和、 点可导,且 (2) (1) (3) Cf x Cf x ( ) ( ) = 推论1 (C为常数)