f3(π)-f3(π)=-+3(2π)>0,
所以f3(π)>f3(π).
答案:B
6.解析:f′(x)=(x+1(2x(x+1)=(x+1(x2+2x),
于是f′(-2)=(-2+1((-2)=0.
答案:0
7.解析:f′(x)=x2+3-a是偶函数,所以f′(-2)=f′(2)=7.
答案:7
8.解析:由f(x)=3x2+2xf′(2),
得f′(x)=6x+2f′(2),
令x=2,得f′(2)=12+2f′(2),
所以f′(2)=-12,
这样f′(x)=6x-24,
故f′(5)=6×5-24=6.
答案:6
9.解:(1)y=tan x=cos x(sin x),
∴y′=cos x(sin x)′=cos2x((sin x)=cos2x(cos2x+sin2x)=cos2x(1).
(2)y′=(xsin x)′-cos x(2)′=sin x+xcos x-cos2x(2sin x).
(3)∵(3xsin x)′=(3x)′sin x+3x(sin x)′=3xln 3sin x+3xcos x=3x(sin xln 3+cos x);
x(cos x-ln x)′
=x2((cos x-ln x)
=x2(x-cos x+ln x)
=x2(-1-xsin x-cos x+ln x),
∴f′(x)=3x(sin xln 3+cos x)+x2(1+xsin x+cos x-ln x).
(4)∵y=2(1)ln(x+1),