Given that the function f (x) = x2-2ax + 5 is an increasing function in the interval [1, + ∞), then the value range of F (- 1) is

Given that the function f (x) = x2-2ax + 5 is an increasing function in the interval [1, + ∞), then the value range of F (- 1) is

The derivative of F (x) = 2x-2a > = 0
x>=a
a