∵c=1f(x)=ax^2+bx+1∵f(-1)=0∴f ‘(x)=2ax+bf ‘(-1)=-2a+b=0f(-1)=a-b+1=0解得a=-1/3 b=2/3∴f(x)==-1/3x^2+2/3x+1
即函数未加绝对值时的最小值大于等于负一且小于零,You do it!