设二次函数f(x)=ax2+bx+c(a≠O)中,
有∣f(0)∣≤1,∣f(1)∣≤1,∣f(-1)∣≤1.求证:对于任意的x∈【-1,1】,有∣f(x)∣≤5/4.
在∣f(1)∣≤1和∣f(0)∣≤1条件下
-b/2a=1/2时取得f(x)最值,a=-b
有什么证据吗?