导数题 无压力
1)
f'(x)=3x^2+2ax
x-3y=0
1/3x=y
k2=-3
f(1)=0
f'(1)=-3
a=-3
b=2
2)f'(x)=3x(x-2)
x1=0x2=2
f(x)max=f(0)=2
f(x)min=f(t)=t^3-3t^2+2