设f(x)={ex,x≤1 ax+b,x>1}在x=1可导,试求a与b 大神求解。

2025-03-06 13:35:54
推荐回答(1个)
回答1:

f(x)
=e^x ,x≤1
=ax+b ,x>1
f(0)=f(0-)=lim(x->0) e^x = 1
f(0+) =lim(x->0) ( ax+b) =b
f(0)=f(0+)=f(0-) => b=1
f'(0-)
=lim(h->0) [e^h - f(0)] /h
=lim(h->0) [e^h - 1] /h
=lim(h->0) h/h
=1
f'(0+)
=lim(h->0) [(ah+1) - f(0)] /h
=lim(h->0) ah /h
=a

f'(0+)=f'(0-) => a=1
ie
(a,b)=(1,1)