Therefore, if m 2-2m-3 < =0, then m={- 1 0 1 2 3}

It is also about Y axis symmetry, x (m2-2m-3) = (-x) (m2-2m-3) = x (m2-2m-3) * (-1) (m2-2m-3).

(- 1)^(m^2-2m-3)= 1

Then m 2-m-3 is an even number, and-1, 1, 3 satisfies the condition.