若f'(1)=3,则lim_(h->0)(f(1)-f(1-2h))/h= ( )_数学解答

若f'(1)=3,则lim_(h->0)(f(1)-f(1-2h))/h= ( )

人气：439 ℃　时间：2020-05-09 17:54:09

解答

lim_(h->0)(f(1)-f(1-2h))/h
=lim_(h->0)2*(f(1)-f(1-2h))/2h
=2*lim_(h->0)(f(1)-f(1-2h))/2h
=2*f'(1)=2*3=6