Задача. Высоты 𝐵𝐵₁ и 𝐶𝐶₁ остроугольного треугольника 𝐴𝐵𝐶 пересекаются в точке 𝐻. Пусть 𝐵₂ и 𝐶₂ — точки на отрезках 𝐵𝐻 и 𝐶𝐻 соответственно такие, что 𝐵𝐵₂ = 𝐵₁𝐻 и 𝐶𝐶₂ = 𝐶₁𝐻. Описанная окружность треугольника 𝐵₂𝐻𝐶₂ пересекает описанную окружность треугольника 𝐴𝐵𝐶 в точках 𝐷 и 𝐸. Докажите, что треугольник 𝐷𝐸𝐻 прямоугольный.
Задача. Высоты 𝐵𝐵₁ и 𝐶𝐶₁ остроугольного треугольника 𝐴𝐵𝐶 пересекаются в точке 𝐻. Пусть 𝐵₂ и 𝐶₂ — точки на отрезках 𝐵𝐻 и 𝐶𝐻 соответственно такие, что 𝐵𝐵₂ = 𝐵₁𝐻 и 𝐶𝐶₂ = 𝐶₁𝐻. Описанная окружность треугольника 𝐵₂𝐻𝐶₂ пересекает описанную окружность треугольника 𝐴𝐵𝐶 в точках 𝐷 и 𝐸. Докажите, что треугольник 𝐷𝐸𝐻 прямоугольный.
One thing that Telegram now offers to all users is the ability to “disappear” messages or set remote deletion deadlines. That enables users to have much more control over how long people can access what you’re sending them. Given that Russian law enforcement officials are reportedly (via Insider) stopping people in the street and demanding to read their text messages, this could be vital to protect individuals from reprisals. Telegram users are able to send files of any type up to 2GB each and access them from any device, with no limit on cloud storage, which has made downloading files more popular on the platform. The regulator said it has been undertaking several campaigns to educate the investors to be vigilant while taking investment decisions based on stock tips. "He has kind of an old-school cyber-libertarian world view where technology is there to set you free," Maréchal said. The regulator said it had received information that messages containing stock tips and other investment advice with respect to selected listed companies are being widely circulated through websites and social media platforms such as Telegram, Facebook, WhatsApp and Instagram.
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