M(x;y)

M'(x;ky)

Phương trình đường tròn:
x² + y² = a²

Phương trình elip:

 \frac{ x² }{a² }  \; + \; \frac{ y² }{ b²} \; = \; 1 \; (b \; = \; ka,k \; < \; 1)   

O_1 = Intersect(yAxis, xAxis)
a = 5.9 (slider from 0 to 15, step 0.1)
O = Intersect(yAxis, xAxis)
c = 4.1 (slider from 1 to 5, step 0.1)
b: sqrt(a * a - c * c)
e: x * x / (a * a) + y * y / (b * b) = 1.0
d = Circle(O, a)
M = Point(d)
f = OrthogonalLine(M, xAxis)
x_1: x(M)
y_1: y(M)
k: b / a
M': (x_1, k * y_1)
A = Intersect(f, xAxis)
g = Segment(M, A)