Cho một mạch gồm biến trở R, cuộn dây không thuần cảm có điện trở r và tụ C mắc nối tiếp. Điều chỉnh R để công suất tiêu thụ trên R là lớn nhất, khi đó điện áp hai đầu đoạn mạch lớn gấp căn 3 lần điện áp hai đầu điện trở. Hệ số công suất của mạch khi đó là

# Read the passage carefully and decide whether the statements are True or False. We can develop alternative sources of energy, and unless we try we’ll never succeed. Instead of using fossil fuels we should be concentrating on more economical uses of electricity, because electricity be produced from any sources of energy. If we didn’t waste so much energy, our resources would last forever. We can save more energy by conservation than we can produce for the same money. Unless we do search on solar energy, wind power, tidal power, hydroelectric plants … our fossil fuels will run out and we’ll freeze or starve from the sun, the waves, and the winds last forever. We won’t really survive unless we aren’t working on cleaner and safer sources of energy. 29. Fossil fuels are renewable sources of energy. 30. Electricity can be produced from the sea. 31. The energy form the sun, the waves and the winds will never be used up. 32. We really need to worry about cleaner and safer sources of energy. ( bổ sung thêm giải thích nữa ạ :<< )

Hình tròn là gì? Hình tam giác là gì? Hình tứ giác là gì? Hình thoi là gì? Số vô tỉ là gì? Số hữu tỉ là gì? Hình vuông là gì? Hình chữ nhật là gì? Hình lập phương là gì?

Mn giúp mk vs mk đang cần gấp

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pop in for a chat whenever you are in town. (HAPPEN) ⇒ if...........................................in town, pop in for a chat.

EX1. 1. He said, “ I have already read this book” => He said …………………………………………………………………………………………….. 2. Join said to his sister, “I want to buy a gift for our mother” => Join told his sister ………………………………………………………………………………… 3. Mrs Brown said, “where are they living?” => Mrs Brown asked me……………………………………………………………………………… 4. “Do you know the girl over there?” Tom said. => Tom asked me ……………………………………………………………………………………… 5. Mother said, “Nam, why don’t you go to bed?” => Mother asked ……………………………………………………………………………………… 6. “May I use your telephone?” said my neighbor. => My neighbor asked me …………………………………………………………………………… 7. The manager said, “come into my office, please.” => The manager told his secretary …………………………………………………………………… 8. “Do not get off the bus while it’s going.” Said the driver => The driver asked the passengers ………………………………………………………………….. 9. She asked to the little boy, “Take a look at yourself in the mirror!” => She told the little boy ……………………………………………………………………………… 10. “Don’t put your elbow on the table!” he said. => He ordered me …………………………………………………………………………………… EX2. 1. He said, “they went away yesterday. => He said ………………………………………………………………………………. 2. “I have lived here for ten years” said Tom. => Tom said ……………………………………………………………………………… 3. The manager said to his assistant, “I’m going to Paris next week.” => The manager said to his assistant, …………………………………………………… 4. My friend said, “ I haven’t done my homework.” => ………………………………………………………………………………………… 5. I think it won’t rain this evening.” Said mother. => ………………………………………………………………………………………… 6. Mr Clack said, “why are you so sad, Join?” => ………………………………………………………………………………………… 7. “Is it time to go?” she wondered. => ………………………………………………………………………………………… 8. They said to me, “do you sleep in the afternoon?” => ………………………………………………………………………………………… 9. “why didn’t you come here last Sunday?” asked Mary. => ………………………………………………………………………………………… 10. The traveler said, “how long does it take to get to Ha Noi by plane?” => …………………………………………………………………………………………

100×10 435×10 112×3 987×5 Cho hay nhất và 5sao

6.The (long)................................ of the experiment is 20 minutes 7.My aunt works as a(chemistry)............................at a university 8.Pupils are very interested in outside class(act)................... 9.Some people play sport to be (health)..............not because they like it 10.Sometimes we are bored and(sleep).................. with his long

Cho tam giác ABC co dien tích 250cm2.canh BC=30cm.tren canh AB lay diem M sao cho AM=2/5 AB. Trên cạnh AC lấy diểm N sao cho AN=2/5 AC. Trên cạnh BC lấy diểm I sao cho BI=2/3 BC. Nối M với N, N với I. Tính dien tich hinh tam giác AMN và dien tich hinh thang MNBI. Tính độ dàu doạn MN