f(x)

%y

%x

Δx

Δy

f(x)=e^x

f(x) = ℯ^(x)
A = Point(f)
g = Tangent(A, f)
h = Line(A, xAxis)
i = Line(A, yAxis)
B = Intersect(h, yAxis)
C = Intersect(xAxis, i)
j = Segment(A, B)
k = Segment(A, C)
H = Point(g)
I = Point(Circle[H, 1])
q = Segment(H, I)
l = OrthogonalLine(I, q)
D = Intersect(g, l)
m = Segment(I, D)