Các bạn ơi giúp mình với ạ mấy bạn giỏi toán và các chuyên gia toán như chuyên gia hangbich , chuyên gia nganna giúp em với ạ !! Cho tam giác ABC nội tiếp đường tròn (O) . Các tia phân giác của góc B và góc C cắt nhau tại I và cắt đường tròn (O) lần lượt tại D và E . Dây DE cắt các cạnh AB và AC lần lượt tại M và N . Chứng minh rằng a) Tam giác AMN là tam giác cân b) Các tam giác EAI và DAI là những tam giác cân c) Tứ giác AMIN là hình thoi

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Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions. The Space of Gong Culture in Central Highlands The space of gong culture in Central Highlands of Viet Nam covers 5 provinces of Kon Turn, Gia Lai, Dak Lak, Dak Nong and Lam Dong. The masters of gong culture are the ethnic groups of Ba Na, Xo Dang, M’Nong, Co Ho, Ro Mam, E De, Giarai... The gong performances are always closely tied to community cultural rituals and ceremonies of the ethnic groups in Central Highlands. Many researchers have classified gongs as ceremonial musical instrument and the gong sounds as a means to communicate with deities and gods. The gongs are made of bronze. Their diameter is from 20cm to 60cm or from 90cm to 120cm. A set of gongs consists of 2 to 12 or 13 units and even to 18 or 20 units in some places. ‎In most of the ethnic groups, namely Giarai, Ede, Kpah, Ba Na, Xo Dang, Brau, Co Ho, etc., only males are allowed to play gongs. However, in others such as Ma and M’Nong groups, both males and females can play gongs. Few ethnic groups (for example, E De Bih), gongs are performed by women only. As for the majority of ethnic groups in Central Highlands, gongs are musical instruments of sacred power. It is believed that every gong is the settlement of a god who gets more powerful as the gong is older. Therefore, gongs are associated to all events in one’s life, such as the inauguration of new houses, funerals, buffalo sacrifice, new harvest, ceremony to pray for people’s and cattle"s health, ceremony to see off soldiers to the front, and the victory celebration. The word “inauguration” in paragraph 4 is closest in meaning to ________. A: sale B: opening C: building D: finding