Evolute of an ellipse

1 · John Cook · Nov. 4, 2022, 12:41 p.m.
Suppose you’re standing on an ellipse. (You actually are: lines of longitude are elliptical because of earth’s equatorial bulge.) Now draw a line perpendicular to where you’re standing. Lines of longitude are nearly circles, but we’ll look at a more obviously elliptical ellipse. The line is perpendicular to the northeast side of the ellipse where […] The post Evolute of an ellipse first appeared on John D. Cook....