总结是对的,前体是导数存在,连续
f'(1)=2
lim(h->0) [f(1+h) -f(1-2h) ]/[e^(2h) -1 ]
=lim(h->0) [f(1+h) -f(1-2h) ]/(2h) (0/0)
分子,分母分别求导
=lim(h->0) [f'(1+h) +2f'(1-2h) ]/2
=3f'(1)/2
=3
/
lim(x->0) [f(1)- f(1-x)] /(2x) =-1 (0/0)
分子,分母分别求导
lim(x->0) f'(1-x) /2 =-1
f'(1)/2 =-1
f'(1) =-2
(1, f(1)) 处的切线方程
y-f(1) = f'(1) (x-1)
y-f(1) = -2(x-1)