# \#intersection

**URL:** https://scanalyst.fourmilab.ch/tag/intersection/4099.md

[Latest](https://scanalyst.fourmilab.ch/latest.md) · [Categories](https://scanalyst.fourmilab.ch/categories.md) · [Tags](https://scanalyst.fourmilab.ch/tags.md)

---

## [Intersections and Tangents of Conic Section Curves](https://scanalyst.fourmilab.ch/t/intersections-and-tangents-of-conic-section-curves/3035)

<div class="topic-metadata">

**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\
**Replies:** 0\
**Last updated:** [12 April 2023 14:07 UTC](https://scanalyst.fourmilab.ch/t/intersections-and-tangents-of-conic-section-curves/3035 "2023-04-12T14:07:41Z")

</div>

How many smooth conic plane curves can be tangent to five given general conic section curves? French mathematician Michel Chasles worked it out in the 19th century, as described in the book 3264 and All Th…