[71] 垂心証明 5通り 初等的からエレガントなべクトルまで

Contents: Thanks for watching. This video is to follow the proof of the existence orthocenter in 5 ways. I can't put more emphasis on how elegant the proof by vector is. 動画の内容：垂心についての解説動画です。五心（重心・内心・外心・垂心・傍心）は有名ではありますが、垂心は他の五心よりも初等的に証明することが複雑な印象があります。いろいろな証明をうわべだけ紹介いたしますが、初等的証明とベクトルを用いた証明をフォローします。特にベクトルの方は必見です。 -------------------------------------------------------------------------------- 主に数学に関することを動画にしています。みんなで面白いことをあーだこーだ言えたらいいなと。 動画に関するアドバイス（声量・ライト・ペン・板書など）や動画にしてほしいことなど何でも受け付けております。むしろください。 連絡等はこちらに→maths.toshi@gmail.com Thanks a ton for visiting here and reading this. Please subscribe this channel and give this video a like if you like it. I usually make videos about mathematics, but any kinds of topics which I find interesting and attractive. All I want to do is just discuss and talk about them, and communicate with people who are into maths, after all. I am afraid to say that I basically speak in Japanese in my videos; however, I am going to try and write things down in the way everyone can comprehend what they are, not without mathematics literacy at least :-). I would appreciate if you gave me any kind of advice ranging from the topics you would like me to bring about to the volume, my handwriting, and the lighting in my videos. Please do not hesitate to leave any comments for this channel growth, and help me to enrich this channel.