chứng minh các hệ thức sau, với điều kiện cho trước: tan(a+b).tanb=(1-k)/(1+k) khi cos(a+2b)=k.cos a

Cho mạch điện gồm các bộ phận :1 nguồn điện(pin), 1 công tắc, 1 bóng đèn và dây dẫn. Hãy vẽ thành một sơ đồ mạch điện và biểu diễn chiều dòng điện chạy qua mạch điện bằng mũi tên

Cho hình tâm giác có d.tích 4,75dm vuông chiều cao ah=2,5dm tính độ dài đáy ac

giúp mik vs ạh! miki đnag cần gấp

VII Put the correct form of the words. 1. We often go to the national park for ............................ (entertain) 2. Cartoon is loved by ............................ (teen) 3. Did you join the sport ............................ last week? (compete) 4. He plays tennis every day. He plays for a famous team. He is (sport) a ............................ man. 5. This river has been ............................ (pollute) 6. I have never seen such a ............................film. (bore) 7. He is a famous tennis ............................ (play) 8. This is the first time I have met such a ............................ girl. (friend) 9. There are a lot of high ............................ in this city. (build) 10. Have you ever visited such a ............................ village? (peace) C. READING VIII Read and fill in the blanks. Tom: Hi there. Ben: Hello Tom. Did you enjoy your holiday? Tom: Yes, It (1.be) ...................... great. I (2.visit) ...................... many interesting places, but I(3. not have) ...................... much time to buy souvenirs. I (4. go) ...................... to the beachand (5. sunbathe) ...................... at weekend. How about your trip to England? Ben: Oh, It (6. not be) ...................... so good. Tom: Really? What (7.do) ...................... you do there? Ben: I (8.get) ...................... sick, so I (9. stay) ...................... in the hotel and (10. watch) ...................... a football match. 1. A. was B. were C. is D. be 2. A. visit B. was visit C. visited D. has visited 3. A. don’t have B. didn’t have C. not had D. didn’t has 4. A. go B. was go C. went D. goes 5. A. sunbathed B. did sunbathe C. don’t sunbathe D. was sunbathe 6. A. wasn’t B. weren’t C. am not D. not was 7. A. do B. done C. doing D. did 8. A. got B. have got C. was get D. to get 9. A. staying B. stayed C. to stay D. did stay 10. A. watched B. watching C. to watch D. has watched IX Fill in each blank with one, two or three words to complete the following sentences. Television watching influences children a lot. American children often spend from three to four hours a day watching TV. Some of them spend more time watching television than studying in the classroom. While television can entertain and inform our children of news and real knowledge, it may also influence them in bad ways. Time spent on watching television takes away their important activities such as reading books, playing outdoor sports, doing homework, having family gatherings and developing social skills. Children can also learn incorrect or inappropriate information from television. If children watch TV a lot, they may have lower grades at school, read fewer books and do less exercise or even be overweight. 1. Children in the USA often spend from ............................... hours a day watching TV. 2. Television can ............................... and provide information for children. 3. Watching TV can take time away from ............................... activities for children. 4. Kids can learn incorrect and unsuitable ............................... on TV. 5. Watching TV a lot may make students have ............................... marks at school. X Read the passage and write TRUE (T) or FALSE (F) into the blank. Yazan likes outdoor sports. He can play volleyball, tennis and badminton. He enjoys swimming and jogging in the morning. He likes summer because he can go swimming every day. He doesn’t like winter because it is very cold. He likes spring when there are a lot of flowers in the garden, but he thinks fall is the best season because the weather is fine and people can play any sports they like. 1. Yazan can’t play badminton. 2. He doesn’t like jogging in the morning. 3. There are many flowers in the spring. 4. The fall season is the best of all. 5. He likes three seasons in a year.

mn giúp em với ạ huhu em cần gấp cho tam giác ABC có AD, BE,CF là các đường phân giác. CMR AE/EC.CD/DB.BF/FA=1

Giải phương trình sau 1,2x^2-5x+1=0 2,4x^2+4x+1=0 3,5x^2-x+2=0

giúp mình gấp nha, có mỗi 1 câu trắc nghiệm thôi

X÷2; y÷3. Và x+y=10 . Giúp mik nha

Từ văn bản hịch tướng sĩ hãy viết 1đv khoảng 12 câu theo kiểu tổng phân hợp nêu suy nghĩ của e về trách nhiệm của công dân vs tổ quốc