1.（0,—2）切线斜率为2/3
y'=3x^2+a 带入x=0,y'=2/3 得a=2/3 即y'=3x^2+2/3
y=x^3+2/3*x+b 带入（0,—2）得b=-2
y=x^3+2/3*x-2
2.=∫(x/f(x))'dx=x/f(x)+C
3.=x^3/3-1/(3x^3)+x+C
4.题意不明
5.题意不明
6.=∫(x^4-1+2)/(x-1)(x^2+1)dx
=∫(x+1+1/(x-1)-(x+1)/(x^2+1))dx
=∫((x+1+1/(x-1)-x/(x^2+1)-1/(x^2+1))dx
=0.5*x^2+x+ln|x-1|-0.5*ln(x^2+1)-arctanx+C
7.f(x)/F(x)=F'(x)/F(x)=(lnF(x))' (F(x)>0绝对值去掉)
=1/(x^2+1)=(arctanx)'
两边积分 lnF(x)=arctanx+C 由F(0)=1得C=0
即F(x)=e^arctanx f(x)=e^(arctanx)/(x^2+1)