r = -0.5 (slider from -5 to 5, step 0.1)
α = 1.5707963267948966 rad (slider from 0 to 6.283185307179586, step 0.7853981633974483)
A = (1, 1)
B = (4, 1)
C = (2, 3)
Matrix1: {{r * cos(α), -1.0 * r * sin(α)}, {r * sin(α), r * cos(α)}}
Vieleck1, a, b, c = Polygon(B, C, A)
A': Matrix1 * A
B': Matrix1 * B
C': Matrix1 * C
Vieleck2, f, d, e = Polygon(A', B', C')
g = Element(Element[Matrix1, 1.0], 1.0)
G = Intersect(xAxis, yAxis)
h = CircleArc(G, A, A')
k = CircleArc(G, B, B')
p = CircleArc(G, C, C')
β = Angle(C, G, C')
i = Segment(G, C)
j = Segment(G, C')
Text1: "\left[ \begin{matrix}" + (Element[Element[Matrix1, 1.0], 1.0]) + "&" + (Element[Element[Matrix1, 1.0], 2.0]) + "\\" + (Element[Element[Matrix1, 2.0], 1.0]) + "&" + (Element[Element[Matrix1, 2.0], 2.0]) + "\end{matrix} \right] \cdot \left[ \begin{matrix}" + (x(C)) + "\\" + (y(C)) + "\end{matrix} \right]  = \left[ \begin{matrix}" + (x(C')) + "\\" + (y(C')) + "\end{matrix} \right]"
l = Segment(G, A)
m = Segment(G, B)
n = Segment(G, C)
q = Segment(C', G)
s = Segment(B', G)
t = Segment(A', G)
a_1 = Segment(B', G)
b_1 = Segment(A', G)
c_1 = Segment(C', G)