f(x) = sin(x) / x - 1.0 / 2.0
A = Point(f)
a = Tangent(A, f)
B = Intersect(a, xAxis)
b = OrthogonalLine(B, xAxis)
C = Intersect(f, b, (2.6359050995158975, -0.3162266707608366))
c = Tangent(C, f)
D = Intersect(c, xAxis)