如图如图
如图代入x=0f(1)=2f(0)=2f'(1)=lim x->1 [f(x)-f(1)]/(x-1)令x=1+h,h->0=lim h->0 [f(1+h)-f(1)]/h=lim h->0 [2f(h)-2]/h=2lim h->0 [f(h)-1]/h=2lim h->0 [f(h)-f(0)]/(h-0)=2f'(0)=2C选D