The Ellipse: Geometry's Best-Kept Secret

What makes an ellipse an ellipse: foci and strings, cone slices, a billiard that always returns, and the perimeter no formula can pin down.

Playlist by @hidden_kepler_orbits

9 tracks, shared on Audicious.

1. Why slicing a cone gives an ellipse (beautiful proof) — 3Blue1Brown
2. Ellipse-billiard simulation — Alexander Gustafsson
3. Why is there no equation for the perimeter of an ellipse‽ — Stand-up Maths
4. Conic sections: Intro to ellipse | Conic sections | Algebra II | Khan Academy — Khan Academy
5. The Best Explanation of the Equation of an Ellipse — mathematicsonline
6. How to find the center, foci and vertices of an ellipse — Brian McLogan
7. Eccentricity of an Ellipse — The Organic Chemistry Tutor
8. Ellipse (string and optical properties) — Ms. Edge
9. What is Ellipse? | Don't Memorise — Sri Chaitanya Academy NEET