a = 0.5 (slider from -5 to 5)
b = 1 (slider from -5 to 5)
c = -3.5 (slider from -5 to 5)
f_1(x) = (a * x^(2)) + (b * x) + c
x_s = -1 (slider from -5 to 5)
y_s = -4 (slider from -5 to 5)
f_2(x) = (a * (x - x_s)^(2)) + y_s
S_2 = Extremum(f_2)
A = Intersect(f_1, yAxis)
t = Tangent(A, f_1)