Через две вершины вписанного четырёхугольника провели произвольную окружность ω. Из двух других вершин провели к ней касательные. (!) Для любой окружности ω прямая через точки касания проходит через фиксированную точку
Через две вершины вписанного четырёхугольника провели произвольную окружность ω. Из двух других вершин провели к ней касательные. (!) Для любой окружности ω прямая через точки касания проходит через фиксированную точку
In 2014, Pavel Durov fled the country after allies of the Kremlin took control of the social networking site most know just as VK. Russia's intelligence agency had asked Durov to turn over the data of anti-Kremlin protesters. Durov refused to do so. On December 23rd, 2020, Pavel Durov posted to his channel that the company would need to start generating revenue. In early 2021, he added that any advertising on the platform would not use user data for targeting, and that it would be focused on “large one-to-many channels.” He pledged that ads would be “non-intrusive” and that most users would simply not notice any change. The next bit isn’t clear, but Durov reportedly claimed that his resignation, dated March 21st, was an April Fools’ prank. TechCrunch implies that it was a matter of principle, but it’s hard to be clear on the wheres, whos and whys. Similarly, on April 17th, the Moscow Times quoted Durov as saying that he quit the company after being pressured to reveal account details about Ukrainians protesting the then-president Viktor Yanukovych. He floated the idea of restricting the use of Telegram in Ukraine and Russia, a suggestion that was met with fierce opposition from users. Shortly after, Durov backed off the idea. Russian President Vladimir Putin launched Russia's invasion of Ukraine in the early-morning hours of February 24, targeting several key cities with military strikes.
from it
