Задача. Окружности 𝑠₁ и 𝑠₂ касаются внешним образом. Их линия центров пересекает 𝑠₁ в точках 𝐴 и 𝑃, и пересекает 𝑠₂ в точках 𝐵 и 𝑃. Общая внешняя касательная касается 𝑠₁ и 𝑠₂ в точках 𝐴₁ и 𝐵₁ соответственно. Прямые 𝐴𝐴₁ и 𝐵𝐵₁ пересекаются в точке 𝑄. Докажите, что 𝑃𝑄 является общей касательной для 𝑠₁ и 𝑠₂.
Желаем вам больше приятных задач по геометрии и не только 📚
Задача. Окружности 𝑠₁ и 𝑠₂ касаются внешним образом. Их линия центров пересекает 𝑠₁ в точках 𝐴 и 𝑃, и пересекает 𝑠₂ в точках 𝐵 и 𝑃. Общая внешняя касательная касается 𝑠₁ и 𝑠₂ в точках 𝐴₁ и 𝐵₁ соответственно. Прямые 𝐴𝐴₁ и 𝐵𝐵₁ пересекаются в точке 𝑄. Докажите, что 𝑃𝑄 является общей касательной для 𝑠₁ и 𝑠₂.
Желаем вам больше приятных задач по геометрии и не только 📚
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. Telegram has become more interventionist over time, and has steadily increased its efforts to shut down these accounts. But this has also meant that the company has also engaged with lawmakers more generally, although it maintains that it doesn’t do so willingly. For instance, in September 2021, Telegram reportedly blocked a chat bot in support of (Putin critic) Alexei Navalny during Russia’s most recent parliamentary elections. Pavel Durov was quoted at the time saying that the company was obliged to follow a “legitimate” law of the land. He added that as Apple and Google both follow the law, to violate it would give both platforms a reason to boot the messenger from its stores. Despite Telegram's origins, its approach to users' security has privacy advocates worried. "Russians are really disconnected from the reality of what happening to their country," Andrey said. "So Telegram has become essential for understanding what's going on to the Russian-speaking world." The gold standard of encryption, known as end-to-end encryption, where only the sender and person who receives the message are able to see it, is available on Telegram only when the Secret Chat function is enabled. Voice and video calls are also completely encrypted.
from tw
