(1)f'(x)=3ax^2+2x+b,g(0)=b=0,g(1)=f(1)+f'(1)=4a+2b+3=4a+3,g(-1)=2a-1因为g(x)=f(x)+f'(x)是奇函数,则g(1)+g(-1)=0,6a+2=0
a= -13 ,f(x)=-13x^3+x^2 (2) f'(x)=-x^2+2x,f'(x)>0,0
(1)f'(x)=3ax^2+2x+b,g(0)=b=0,g(1)=f(1)+f'(1)=4a+2b+3=4a+3,g(-1)=2a-1因为g(x)=f(x)+f'(x)是奇函数,则g(1)+g(-1)=0,6a+2=0
a= -13 ,f(x)=-13x^3+x^2 (2) f'(x)=-x^2+2x,f'(x)>0,0