В остроугольном треугольнике ABC отметили центр описанной окружности O и ортоцентр H. Перпендикуляр из H на AO пересекает BC в точке X. Перпендикуляр в X к BC вместе с прямыми AB и AC ограничивает треугольник Δ. Точка S — центр описанной окружности треугольника Δ. Докажите, что SX касается окружности (ABC).
В остроугольном треугольнике ABC отметили центр описанной окружности O и ортоцентр H. Перпендикуляр из H на AO пересекает BC в точке X. Перпендикуляр в X к BC вместе с прямыми AB и AC ограничивает треугольник Δ. Точка S — центр описанной окружности треугольника Δ. Докажите, что SX касается окружности (ABC).
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. This ability to mix the public and the private, as well as the ability to use bots to engage with users has proved to be problematic. In early 2021, a database selling phone numbers pulled from Facebook was selling numbers for $20 per lookup. Similarly, security researchers found a network of deepfake bots on the platform that were generating images of people submitted by users to create non-consensual imagery, some of which involved children. The Securities and Exchange Board of India (Sebi) had carried out a similar exercise in 2017 in a matter related to circulation of messages through WhatsApp. Artem Kliuchnikov and his family fled Ukraine just days before the Russian invasion. But Telegram says people want to keep their chat history when they get a new phone, and they like having a data backup that will sync their chats across multiple devices. And that is why they let people choose whether they want their messages to be encrypted or not. When not turned on, though, chats are stored on Telegram's services, which are scattered throughout the world. But it has "disclosed 0 bytes of user data to third parties, including governments," Telegram states on its website.
from cn
