Нехай 𝑂 та 𝐻 — центр описаного кола та ортоцентр гострокутного трикутника 𝐴𝐵𝐶. На сторонах 𝐴𝐶 та 𝐴𝐵 відмітили точки 𝐷 та 𝐸 відповідно так, що відрізок 𝐷𝐸 проходить через точку 𝑂 та 𝐷𝐸||𝐵𝐶. На стороні 𝐵𝐶 обрали точки 𝑋 та 𝑌 такі, що 𝐵𝑋 = 𝑂𝐷 та 𝐶𝑌 = 𝑂𝐸. Доведіть, що ∠𝑋𝐻𝑌 + 2∠𝐵𝐴𝐶 = 180°.
Нехай 𝑂 та 𝐻 — центр описаного кола та ортоцентр гострокутного трикутника 𝐴𝐵𝐶. На сторонах 𝐴𝐶 та 𝐴𝐵 відмітили точки 𝐷 та 𝐸 відповідно так, що відрізок 𝐷𝐸 проходить через точку 𝑂 та 𝐷𝐸||𝐵𝐶. На стороні 𝐵𝐶 обрали точки 𝑋 та 𝑌 такі, що 𝐵𝑋 = 𝑂𝐷 та 𝐶𝑌 = 𝑂𝐸. Доведіть, що ∠𝑋𝐻𝑌 + 2∠𝐵𝐴𝐶 = 180°.
Markets continued to grapple with the economic and corporate earnings implications relating to the Russia-Ukraine conflict. “We have a ton of uncertainty right now,” said Stephanie Link, chief investment strategist and portfolio manager at Hightower Advisors. “We’re dealing with a war, we’re dealing with inflation. We don’t know what it means to earnings.” "For Telegram, accountability has always been a problem, which is why it was so popular even before the full-scale war with far-right extremists and terrorists from all over the world," she told AFP from her safe house outside the Ukrainian capital. But Kliuchnikov, the Ukranian now in France, said he will use Signal or WhatsApp for sensitive conversations, but questions around privacy on Telegram do not give him pause when it comes to sharing information about the war. 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. The company maintains that it cannot act against individual or group chats, which are “private amongst their participants,” but it will respond to requests in relation to sticker sets, channels and bots which are publicly available. During the invasion of Ukraine, Pavel Durov has wrestled with this issue a lot more prominently than he has before. Channels like Donbass Insider and Bellum Acta, as reported by Foreign Policy, started pumping out pro-Russian propaganda as the invasion began. So much so that the Ukrainian National Security and Defense Council issued a statement labeling which accounts are Russian-backed. Ukrainian officials, in potential violation of the Geneva Convention, have shared imagery of dead and captured Russian soldiers on the platform.
from pl
