aa<-b<6a,a>0,则函数f(x)=ax^2+bx+c在【-2,3】上最大值、最小值分别为
af(x)=a[x+b/(2a)]^2+c-b^2/(4a)a>0,1/2
1/2<-b/(2a)<3属于【-2,3】,在对称轴上取最小值!