f(x) = If[abs(x) ≤ (2 * π), sin(x)]
a = 1.3168146928204143 (slider from (-2 * π) to (2 * π), step 0.1)
A: (a, f(a))
puutuja = Tangent(a, f)
d = Circle(A, 2)
B = Intersect(d, puutuja, 1)
C = Intersect(d, puutuja, 2)
g = Segment(B, C)
h = Derivative(f)