f'(x0)=4,则lim(k→0)[f(x0)-f(x0-k)]/(4k)=
问题描述:
f'(x0)=4,则lim(k→0)[f(x0)-f(x0-k)]/(4k)=
答
lim(k→0)[f(x0)-f(x0-k)]/(4k)
=(1/4)lim(k→0)[f(x0)-f(x0-k)]/k
=(1/4)f'(x0)
=1