7.解析:f(x)dx=(ax2+c)dx
=
=+c=ax20+c,
∵0≤x0≤1,∴x0=.
答案:
8.解析:f(x)dx=|x|dx+(-ex)dx
=xdx+(-ex)dx=x2+(-ex)
=-e2+e.
答案:-e2+e
9.解:(1)(2sin x-3cos x)dx
=2sin xdx-3cos xdx
=2(-cos x)-3sin x
=2-3
=2-3=3.
(2)由=得dx
=xdx+(-x)dx=x2-x2=a2.
(3)f(x)==-,
取F(x)=ln x-ln(x+1)=ln ,
则F′(x)=-.