设f’（x0）=A，求limh趋于0f（x02h）-f（x0）/h

更新时间2022-03-08 00:28:14

f'(a)=A

lim【h→0】{[f(a+2n)-f(a)]/h}

=lim【h→0】{2[f(a+2h)-f(a)]/(2h)}

=2f'(a)

=2A