用导数定义求导数

Question

如题所述

Answer 1

Answer 2

f(x) =y= 1-x
dydx = lim(h->0)[ f(x+h) -f(x)] /h
= lim(h->0)[1- (x+h) -(1-x))] /h
= lim(h->0)-h/h
=-1

f(x) =y = √x
dydx = lim(h->0)[ f(x+h) -f(x)] /h
= lim(h->0)[ √(x+h) -√x] /h
= lim(h->0)[ √x+ (1/2)h/√x +...) -√x] /h
= lim(h->0)(1/2)[h/√x]/h
= 1/(2√x)本回答被网友采纳