f(x)=cos x(x+|sin x| ),则在x=0处有.(A)f'(X)=2 (B)f'(x) =1 (C)f'(x) =0 (D)f'(x) 不可导.

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f(x)=cos x(x+|sin x| ),则在x=0处有.(A)f'(X)=2 (B)f'(x) =1 (C)f'(x) =0 (D)f'(x) 不可导.
f(x)=cos x(x+|sin x| ),则在x=0处有.(A)f'(X)=2 (B)f'(x) =1 (C)f'(x) =0 (D)f'(x) 不可导.

f(x)=cos x(x+|sin x| ),则在x=0处有.(A)f'(X)=2 (B)f'(x) =1 (C)f'(x) =0 (D)f'(x) 不可导.
f(x)=cos x(x+|sin x| )
x-->+0
lim f(x)=lim 2xcos x
f'(0)=2cosx-2xsinx=2
x-->-0
lim f(x)=lim cos x*0=0
(D)f'(x) 不可导.