a

a+Δx

f(x) = x^(2) + 1
A = Point(f)
B = Point(f)
a = Line(A, B)
C: (x(A), 0)
D: (x(B), 0)
b = Segment(A, C)
c = Segment(B, D)
d = Tangent(A, f)
a_1 = Slope(a)
a_2 = Slope(d)