y=sin(x)

y=cos(x)

f(x) = If[abs(x) ≤ (2 * π), sin(x)]
a = -0.8831853071795859 (slider from (-2 * π) to (2 * π))
A: (a, f(a))
g = Tangent(a, f)
h = Derivative(f)
c = Circle(A, 1.4)
B, C = Intersect(c, g)
i = Segment(B, C)