F(x)=f(x)(1+|sinx|),F(x),f(x)在x=0处可导,求f(0)

来源:学生作业帮助网 编辑:作业帮 时间:2024/07/08 11:43:54
F(x)=f(x)(1+|sinx|),F(x),f(x)在x=0处可导,求f(0)
x)sӨдM5řy5: 19+*l .iyڿ=:66ih$铧QΆ;Ձ,ۜ ];hT3tAb+@+`3! dBHD쐧ۗ=r]5`toFU у7{{v0tu6<ٽh0 M|m]}@!\'^4 b<[,jg_\g y0 Gi*h` G`0L@bP (]JN@ߡ P%-={zv0C 2 E$H

F(x)=f(x)(1+|sinx|),F(x),f(x)在x=0处可导,求f(0)
F(x)=f(x)(1+|sinx|),F(x),f(x)在x=0处可导,求f(0)

F(x)=f(x)(1+|sinx|),F(x),f(x)在x=0处可导,求f(0)
F'(0)=lim{x->0}[f(x)(1+|sinx|)-f(0)]/x=lim{x->0}[f(x)-f(0)](1+|sinx|)/x+lim{x->0}[f(0)(1+|sinx|)-f(0)]/x=f'(0)+lim{x->0}f(0)|sinx|/x
左极限lim{x->0-}f(0)|sinx|/x=-f(0),右极限lim{x->0+}f(0)|sinx|/x=f(0).
因为F'(0)存在,所以左导数等于右导数,从而f'(0)-f(0)=f'(0)+f(0),因此f(0)=0.

F'(0)=lim(x->0) (f(x)(1+|sinx|)-f(0))/x-0=f'(x)(可导)+lim(x->0) f(x)|sinx|/x
lim(x->0) f(x)|sinx|/x 左极限为-f(0),右极限为f(0)
F(x)在0处可导,则左右极限相等,-f(0)=f(0),f(0)=0