Brian Lawrence showed me the following conceptual proof of Poncelet porism in the case of two circles, which I thought was neat and wanted to sketch here. (This is only a sketch, since I'm not really defining the integration.) Let $latex {P}&fg=000000$ be a point on the outer circle, and let $latex {Q}&fg=000000$ be the… Continue reading A proof of Poncelet Porism with two circles
The story of the AutoCarrot
1. Glazed carrots Okay. Imagine you’re, like, trying to make glazed carrots or something. Maybe a really simplified recipe looks something like: Cut your carrots into suitably sized pieces with a knife. Use a measuring spoon to get the right amount of oil, sugar, salt, etc. Throw the carrots and other ingredients into a frying… Continue reading The story of the AutoCarrot
OTIS X applications are open
The tenth year of OTIS is now accepting applications. Due August 1, 2024 for regular deadline and April 30, 2025 for late applications. https://web.evanchen.cc/otis.html#apply The application and syllabus are pretty much going to be the same as in previous years; here are some of the (mostly small) changes: I deleted the question that used to… Continue reading OTIS X applications are open
Infinitely many stages of grief
Where do all the smart, curious, earnest kids go these days? One of my friends asked me this recently, and I wasn’t sure what to say. In the last ten years, something has changed. If I had to summarize my concerns in one sentence, I would say this: kids these days no longer feel they’re… Continue reading Infinitely many stages of grief
(EC)⁵: College Essay Consulting
Calling all high school juniors! We’re proud to announce a new educational service to accompany last year’s ⛵IS: Evan’s Chen’s Elite Cutting-Edge College Essay Consulting & Editing Center! Abbreviated (EC)⁵. Why trust Evan? Evan Chen is one of the leading names in admissions to elite American colleges. Students that Evan has mentored have gone on… Continue reading (EC)⁵: College Essay Consulting
Brianchon is fair game
About five years ago I wrote a blog post warning that I thought it was a bad idea to design math olympiads to be completely untrainable, because I think math olympiads should be about talent development rather than just talent identification, yada yada yada. So now I want to say the other direction: I also… Continue reading Brianchon is fair game
NP-hard advice questions
Sometimes I get asked broad advice questions on solving problems, for example questions like: How do I know when to switch or prioritize approaches I come up with? How do I know which points or lines to add in geometry problems? How can I tell if I’m making progress on a problem? How can I… Continue reading NP-hard advice questions
Against exploitable rubrics
Editorial note: this post was mostly written in February 2023. Any resemblance to contests after that date is therefore coincidental. Background A long time ago, rubrics for the IMO and USAMO were fairly strict. Out of seven, the overall meta-rubric looks like: 7: Problem solved 6: Tiny slip (and contestant could repair) 5: Small gap… Continue reading Against exploitable rubrics
January newsflash
Here’s a mix of several publicity-related things I’d like to broadcast. AlphaGeometry A lot of you have already heard the buzz about the AlphaGeometry news and Nature paper. (I’ve known about this paper for a while now, so I’m glad I can finally talk about it!) I managed to snag a cameo in the DeepMind… Continue reading January newsflash
MOHS was a mistake
I remember reading a Paul Graham essay about how people can’t think clearly about parts of their identity. In my students, I have never seen this more clearly than when people argue about the difficulty of problems. Some years ago I published a chart of my ratings of problem difficulty, using a scale called MOHS.… Continue reading MOHS was a mistake
Power Overwhelming 