In st 2 is still true if A = 0 => B and D and C are all out
In st 1, (x-1)^2 +A >= A with all x
Therefore "x^2-2x+A is positive for all x" can be true only if A >= 1 => A is positive
In st 1, (x-1)^2 +A >= A with all x
Therefore "x^2-2x+A is positive for all x" can be true only if A >= 1 => A is positive