Un conte tout droit
Marie Lhuissier tells a story of freedom, gained thanks to curvature, of children who take a tangent in a world of adults educated to go straight...
With her friend О́льга, they also make #StreetMath on this theme by making a parabola using the algorithm of Casteljau.
We asked ourselves a few questions, and here is the answer. In particular, if we take two points of a parabola whose tangents are perpendicular, these tangents intersect on the directrix of the parabola, which makes the construction of the focus very simple to achieve with rope.
You can move the points A,B,C that define the frame, the point E that defines the number of lines, a point M (+) on the parabola, and display or not the focus and the director line D, or a ray parallel to the axis of the parabola, and its reflection on the parabola.