Given that the increasing function of function f (x) = x to the second power-2ax-3 is [1, + ∞), then the value of real number a is

Given that the increasing function of function f (x) = x to the second power-2ax-3 is [1, + ∞), then the value of real number a is

f(x)=x²-2ax-3=(x-a)²-3-a²
a=1