Cho tam giác ABC nội tiếp đường tròn (O), các đường cao AD, BE, CF cắt nhau tại H và lần lượt cắt đường tròn tại M, N, P. Chứng minh rằng:
1) Tứ giác BFEC và AEDB nội tiếp.
2) AE.AC = AF.AB.
3) Chứng minh H là tâm đường tròn nội tiếp tam giác EFD.
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Số lượng câu hỏi
8
Số lượng câu trả lời
1
Điểm GP
0
Điểm SP
0
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Chủ đề:
TEST 1Câu hỏi:
My grandmother is more than ninety years old which makes her the oldest person in the whole family. Despite her old age, her memory is still fresh. She always tells us that many things used to be different when she was young.
My grandma used to begin her day very early. She used to start her day at 4 o'clock while everybody else was still in beds. She used to do all the housework by herself. She used to make clothes for her children and as for her outdoor work, she used to raise some chicken and sheep and she also used to help the males to grow vegetables. There didn't use to be many pastime activities. Her hobby used to be listening to the radio. In the evening all the family used to sit by the fire in the sitting room where all the family gathered at night to tell stories or discuss family matters as weddings, harvest time or to assign the next day's work.
When a member of the family was ill, she used to show him which herbs to use. She collected them from the near forest or from the mountain. My grandma used to know so many effective methods to cure illnesses.
1. How is the memory of the writer's grandmother?
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2. What time did she use to start her day?
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3. What did she use to do in her pastimes?
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4. Where did her family use to sit in the evening?
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5. What did she usually do when a member of the family was ill?
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