user-avatar
chayngaydi
2 năm trước
Cho tam giác DEF cân tại D(D<90').Vẽ DH vuông góc với EF(H thuộc EF).Chứng minh rằng DH là tia phân giác của EDF. (vẽ hình nha các bạn)
Thích Trả lời Chia sẻ

Các câu hỏi liên quan

Coal, oil, and natural gas supply human being with most of its power. However, not only are supplies of these fuels limited, but they are a major resource of pollution. Therefore, it’s important to improve, explore and develop such alternative energy sources as nuclear, water, solar, and wind power. Each of these alternatives, however, has advantages and disadvantages. Nuclear power factories efficiently produce large amount of electricity without polluting the atmosphere; however, they are costly to build and maintain, and thy are the difficult problem of what to do with nuclear waste. Hydroelectric power in expensive and environmentally safe, but impractical for communities located far from moving water. Wing power is pollution-free source of renewable energy but it cannot be used in many parts of the world where there is insufficient wind. Solar power is renewable, it does not cause pollution and it does not add the earth’s heat load. However, it is difficult to collect and store. Solar power also requires expensive equipment. 1. Coal, oil and natural gas are pollution-free sources of energy. 2. Hydroelectric power is expensive and always available everywhere. 3. Wind power doesn’t pollute the environment. 4. Solar power is never completely used up. B. Choose the best answer: 5. Nuclear power factories ………. A. are difficult to build B. pollute the atmosphere C. are very cheap to maintain D. create the problem of nuclear waste 6. What is the advantage of these alternatives ? A. They are environmentally friendly energy sources B. They are non-renewable forms of energy C. They are all very practical D. They are inexpensive to exploit

2018 © Loga - Không Ngừng Sáng Tạo - Bùng Cháy Đam Mê
Loga Team