Через центр O описанной окружности треугольника ABC проведена прямая, пересекающая стороны AB, BC и CA в точках F, D и E соответственно. Докажите, что окружности, построенные на AD, BE и CF как на диаметрах пересекаются в двух точках, одна из которых лежит на описанной окружности треугольника ABC, а вторая на окружности девяти точек.
Через центр O описанной окружности треугольника ABC проведена прямая, пересекающая стороны AB, BC и CA в точках F, D и E соответственно. Докажите, что окружности, построенные на AD, BE и CF как на диаметрах пересекаются в двух точках, одна из которых лежит на описанной окружности треугольника ABC, а вторая на окружности девяти точек.
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 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. Either way, Durov says that he withdrew his resignation but that he was ousted from his company anyway. Subsequently, control of the company was reportedly handed to oligarchs Alisher Usmanov and Igor Sechin, both allegedly close associates of Russian leader Vladimir Putin. To that end, when files are actively downloading, a new icon now appears in the Search bar that users can tap to view and manage downloads, pause and resume all downloads or just individual items, and select one to increase its priority or view it in a chat. 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.
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