$ \mathscr{C}_f $

$ T $

$ T_1 $

$ T_2 $

f = Function(0.8 * x^(2) + 7 * x, 0, 15)
A = Point(f)
a = Tangent(A, f)
a_1 = Slope(a)
B = Intersect(yAxis, xAxis)
b = Tangent(B, f)
C = Point(f)
c = Tangent(C, f)
a_2 = Slope(c)
a_3 = Slope(c)
a_4 = Slope(b)