设f(x) 可导,且f(1)=0 ,则lim x趋向与1时f(x)/x-1=( )
问题描述:
设f(x) 可导,且f(1)=0 ,则lim x趋向与1时f(x)/x-1=( )
答
lim (x->1) f(x)/(x-1)
= lim (x->1) [ f(x) - f(1)] /(x-1)
= f '(1)