Question

已知函数f(x)=ax^2+bx+c满足f(1)=0,a＞b＞c,求c／a的取值范围

Answer 1

f(1)=a+b+c=0

a＞b＞c

=>a＞-a-c＞c

=> 2a>-c,-a>2c

由2a>-c,a>c

=>3a>0

由-a>2c,a>c

=>0>3c

c>-2a,-a>2c(a>0,cc/a>-2