Задача 56: Автор - Григорий Забазнов Источник: MGO 2024, задача 4
На сторонах AB и AC треугольника ABC выбраны точки E и F соответственно так,что B,E,F,C лежат на одной окружности. Прямые BF и CE пересекаются в точке K. Отражение прямой AK относительно биссетрисы угла BAC пересекает BF и CE в точках M и N. Доказать, что если окружность (MKN) касается BC, то она касается и EF.
Задача 56: Автор - Григорий Забазнов Источник: MGO 2024, задача 4
На сторонах AB и AC треугольника ABC выбраны точки E и F соответственно так,что B,E,F,C лежат на одной окружности. Прямые BF и CE пересекаются в точке K. Отражение прямой AK относительно биссетрисы угла BAC пересекает BF и CE в точках M и N. Доказать, что если окружность (MKN) касается BC, то она касается и EF.
At this point, however, Durov had already been working on Telegram with his brother, and further planned a mobile-first social network with an explicit focus on anti-censorship. Later in April, he told TechCrunch that he had left Russia and had “no plans to go back,” saying that the nation was currently “incompatible with internet business at the moment.” He added later that he was looking for a country that matched his libertarian ideals to base his next startup. Telegram does offer end-to-end encrypted communications through Secret Chats, but this is not the default setting. Standard conversations use the MTProto method, enabling server-client encryption but with them stored on the server for ease-of-access. This makes using Telegram across multiple devices simple, but also means that the regular Telegram chats you’re having with folks are not as secure as you may believe. Oleksandra Matviichuk, a Kyiv-based lawyer and head of the Center for Civil Liberties, called Durov’s position "very weak," and urged concrete improvements. "There is a significant risk of insider threat or hacking of Telegram systems that could expose all of these chats to the Russian government," said Eva Galperin with the Electronic Frontier Foundation, which has called for Telegram to improve its privacy practices. Messages are not fully encrypted by default. That means the company could, in theory, access the content of the messages, or be forced to hand over the data at the request of a government.
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