T449

a = -5 (slider from -5 to 5)
eq1: x^(2) + y^(2) - (4 * y) + a = 0
A = Center(eq1)
eq2: x^(2) + y^(2) + ((2 * a) * x) - (a * y) + a = 0
f: y = (-1 / 2 * x)
eq3: x^(2) + y^(2) - ((2 * a) * x) - ((4 * a) * y) + (4 * a^(2)) - 1 = 0
g: y = (2 * x)