Try to move the number “a” on the slider
(select it and then use the arrows on your keyboard).
Observe that when “a” reaches exactly the value 0,
the point P on the graph becomes “undefined”.

f(x) = (ℯ^(x) - 1) / x
a = 0.84 (slider from -1 to 1, step 0.01)
P: (a, f(a))
g = OrthogonalLine(P, yAxis)
h = OrthogonalLine(P, xAxis)
A = Intersect(g, yAxis)
B = Intersect(h, xAxis)
u = Vector(B, P)
v = Vector(P, A)