なぜ円錐の断面は楕円になるのか

We have two announcements. 1. We have an official Japanese Twitter account.   / 3b1bjp   This account will post video updates and other information. Please note that we cannot respond to individual DMs or replies. 2. We will not be posting in December 2022 This channel is run by volunteer students from the University of Tokyo, but we will not be posting in December as the people behind the channel will be very busy. This video is a translation and re-edit of a 3blue1brown video by a volunteer group from the University of Tokyo, and is published under an official license. Please subscribe to the channel and give it a high rating! Original video (English)    • Why slicing a cone gives an ellipse (beaut...   This video is a translation and re-edit of a 3Blue1Brown video by a volunteer group from the University of Tokyo, and is published under an official license. Please subscribe to the channel and give it a high rating! Original channel (English)    / 3blue1brown   Music by Vincent Rubinetti Download the music on Bandcamp: https://vincerubinetti.bandcamp.com/a... Stream the music on Spotify: https://open.spotify.com/album/1dVyjw...