2t

O = Intersect(xAxis, yAxis)
c = Circle(O, 1)
A_1 = Intersect(c, xAxis, 2)
n = 5 (slider from 3 to 13, step 2)
A = Sequence(Rotate[A_1, ((k * 2) * π / n), O], k, 0, n - 1)
l1 = Sequence(Segment[O, Element[A, k]], k, 1, n)
l3 = Append(Sequence[Segment[Element[A, k], Element[A, k + 1]], k, 1, n - 1], Segment[Element[A, 1], Element[A, n]])
A_n = Element(A, n)
A_2 = Element(A, 2)
d = Arc(c, A_n, A_1)
P = Point(d)
l2 = Sequence(Segment[P, Element[A, k]], k, 1, n)
f = Segment(O, P)
α = Angle(P, O, A_1)
Lp = Sequence(Length[Element[l2, (2 * k)]], k, 1, (n - 1) / 2)
Li = Sequence(Length[Element[l2, (2 * k) - 1]], k, 1, (n + 1) / 2)
S_i = Sum(Li)
S_p = Sum(Lp)
texte1: "impairs = " + Li + ", somme = " + S_i + "
pairs = " + Lp + ", somme = " + S_p + ""